#include <bits/stdc++.h>
using namespace std;
class IO {
  static const int bufSize = 1 << 18;
  char inBuf[bufSize], outBuf[bufSize];
  char *ip1 = inBuf, *ip2 = inBuf;
  int ok = 1, op1 = -1, op2 = bufSize - 1;
  template <typename T>
  __inline__ __attribute__((always_inline)) void __RI(T& x) {
    int ch = gc(), neg = 1;
    x = 0;
    for (; !(ch == EOF || isdigit(ch) || ch == '-'); ch = gc())
      ;
    if (ch == EOF) {
      ok = 0;
      return;
    }
    if (ch == '-') neg = -1, ch = gc();
    for (; isdigit(ch); ch = gc()) x = x * 10 + (ch - 48) * neg;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) void __RC(T& x) {
    unsigned char ch;
    while (isspace(ch = gc()))
      ;
    if (ch == EOF) {
      ok = 0;
      return;
    }
    x = ch;
  }
  __inline__ __attribute__((always_inline)) void __RS(string& x) {
    char ch;
    x.clear();
    for (ch = gc(); isspace(ch); ch = gc())
      ;
    if (ch == EOF) {
      ok = 0;
      return;
    }
    for (; !isspace(ch); ch = gc()) x.push_back(ch);
  }

 public:
  __inline__ __attribute__((always_inline)) int gc() {
    return ip1 == ip2 && (ip2 = (ip1 = inBuf) + fread(inBuf, 1, bufSize, stdin),
                          ip1 == ip2)
               ? EOF
               : *ip1++;
  }
  __inline__ __attribute__((always_inline)) IO& R(char& x) {
    __RC(x);
    return *this;
  }
  __inline__ __attribute__((always_inline)) IO& R(unsigned char& x) {
    __RC(x);
    return *this;
  }
  __inline__ __attribute__((always_inline)) IO& R(string& x) {
    __RS(x);
    return *this;
  }
  template <typename T1, typename T2>
  __inline__ __attribute__((always_inline)) IO& R(pair<T1, T2>& x) {
    R(x.first), R(x.second);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& R(vector<T>& x) {
    for (auto& i : x) R(i);
    return *this;
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& RA(T* a, int n) {
    for (int i = 0; i < n; ++i) R(a[i]);
    return *this;
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& R(T& x, Args&... args) {
    R(x), R(args...);
    return *this;
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& RA(T* a, int n, Args... args) {
    for (int i = 0; i < n; ++i) RA(a[i], args...);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& R(T& x) {
    static_assert(is_integral<T>::value, "Unsupported types");
    if (is_integral<T>::value) __RI(x);
    return *this;
  }

 private:
  char space = ' ';
  template <typename T>
  __inline__ __attribute__((always_inline)) void __WI(T x) {
    static char buf[64];
    static int len = -1;
    if (x >= 0) {
      do {
        buf[++len] = x % 10 + 48, x /= 10;
      } while (x);
    } else {
      pc('-');
      do {
        buf[++len] = -(x % 10) + 48, x /= 10;
      } while (x);
    }
    while (len >= 0) {
      pc(buf[len]), --len;
    }
  }

 public:
  __inline__ __attribute__((always_inline)) void pc(const char& x) {
    if (op1 == op2) flush();
    outBuf[++op1] = x;
  }
  __inline__ __attribute__((always_inline)) void flush() {
    fwrite(outBuf, 1, op1 + 1, stdout), op1 = -1;
  }
  __inline__ __attribute__((always_inline)) IO& W(const char& x) {
    pc(x);
    return *this;
  }
  __inline__ __attribute__((always_inline)) IO& W(const char* x) {
    while (*x != '\0') pc(*(x++));
    return *this;
  }
  __inline__ __attribute__((always_inline)) IO& W(const string& x) {
    W(x.c_str());
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& W(const vector<T>& x) {
    for (auto& i : x) WS(i);
    WL();
    return *this;
  }
  __inline__ __attribute__((always_inline)) IO& WL() {
    W('\n');
    return *this;
  }
  template <typename T1, typename T2>
  __inline__ __attribute__((always_inline)) IO& W(const pair<T1, T2>& x) {
    WS(x.first), W(x.second);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& WL(const T& x) {
    W(x), W('\n');
    return *this;
  }
  __inline__ __attribute__((always_inline)) IO& WS() {
    W(space);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& WS(const T& x) {
    W(x), W(space);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& WA(T* a, int n) {
    for (int i = 0; i < n; i++) WS(a[i]);
    WL();
    return *this;
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& W(const T& x,
                                                  const Args&... args) {
    W(x), W(space), W(args...);
    return *this;
  }
  template <typename... Args>
  __inline__ __attribute__((always_inline)) IO& WS(const Args&... args) {
    W(args...), W(space);
    return *this;
  }
  template <typename... Args>
  __inline__ __attribute__((always_inline)) IO& WL(const Args&... args) {
    W(args...), W('\n');
    return *this;
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& WA(T* a, int n, Args... args) {
    for (int i = 0; i < n; i++) WA(a[i], args...);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& W(const T& x) {
    static_assert(is_integral<T>::value, "Unsupported types");
    if (is_integral<T>::value) __WI(x);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& operator>>(T& x) {
    R(x);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& operator<<(const T& x) {
    W(x);
    return *this;
  }
  bool good() { return ok; }
  IO() {}
  ~IO() { flush(); }
} io;
const int32_t INF = 0x3f3f3f3f;
const int64_t INFL = 0x3f3f3f3f3f3f3f3fLL;
vector<int> primes = {
    2,    3,    5,    7,    11,   13,   17,   19,   23,   29,   31,   37,
    41,   43,   47,   53,   59,   61,   67,   71,   73,   79,   83,   89,
    97,   101,  103,  107,  109,  113,  127,  131,  137,  139,  149,  151,
    157,  163,  167,  173,  179,  181,  191,  193,  197,  199,  211,  223,
    227,  229,  233,  239,  241,  251,  257,  263,  269,  271,  277,  281,
    283,  293,  307,  311,  313,  317,  331,  337,  347,  349,  353,  359,
    367,  373,  379,  383,  389,  397,  401,  409,  419,  421,  431,  433,
    439,  443,  449,  457,  461,  463,  467,  479,  487,  491,  499,  503,
    509,  521,  523,  541,  547,  557,  563,  569,  571,  577,  587,  593,
    599,  601,  607,  613,  617,  619,  631,  641,  643,  647,  653,  659,
    661,  673,  677,  683,  691,  701,  709,  719,  727,  733,  739,  743,
    751,  757,  761,  769,  773,  787,  797,  809,  811,  821,  823,  827,
    829,  839,  853,  857,  859,  863,  877,  881,  883,  887,  907,  911,
    919,  929,  937,  941,  947,  953,  967,  971,  977,  983,  991,  997,
    1009, 1013, 1019, 1021, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069,
    1087, 1091, 1093, 1097, 1103, 1109, 1117, 1123, 1129, 1151, 1153, 1163,
    1171, 1181, 1187, 1193, 1201, 1213, 1217, 1223, 1229, 1231, 1237, 1249,
    1259, 1277, 1279, 1283, 1289, 1291, 1297, 1301, 1303, 1307, 1319, 1321,
    1327, 1361, 1367, 1373, 1381, 1399, 1409, 1423, 1427, 1429, 1433, 1439,
    1447, 1451, 1453, 1459, 1471, 1481, 1483, 1487, 1489, 1493, 1499, 1511,
    1523, 1531, 1543, 1549, 1553, 1559, 1567, 1571, 1579, 1583, 1597, 1601,
    1607, 1609, 1613, 1619, 1621, 1627, 1637, 1657, 1663, 1667, 1669, 1693,
    1697, 1699, 1709, 1721, 1723, 1733, 1741, 1747, 1753, 1759, 1777, 1783,
    1787, 1789, 1801, 1811, 1823, 1831, 1847, 1861, 1867, 1871, 1873, 1877,
    1879, 1889, 1901, 1907, 1913, 1931, 1933, 1949, 1951, 1973, 1979, 1987,
    1993, 1997, 1999, 2003, 2011, 2017, 2027, 2029, 2039, 2053, 2063, 2069,
    2081, 2083, 2087, 2089, 2099, 2111, 2113, 2129, 2131, 2137, 2141, 2143,
    2153, 2161, 2179, 2203, 2207, 2213, 2221, 2237, 2239, 2243, 2251, 2267,
    2269, 2273, 2281, 2287, 2293, 2297, 2309, 2311, 2333, 2339, 2341, 2347,
    2351, 2357, 2371, 2377, 2381, 2383, 2389, 2393, 2399, 2411, 2417, 2423,
    2437, 2441, 2447, 2459, 2467, 2473, 2477, 2503, 2521, 2531, 2539, 2543,
    2549, 2551, 2557, 2579, 2591, 2593, 2609, 2617, 2621, 2633, 2647, 2657,
    2659, 2663, 2671, 2677, 2683, 2687, 2689, 2693, 2699, 2707, 2711, 2713,
    2719, 2729, 2731, 2741, 2749, 2753, 2767, 2777, 2789, 2791, 2797, 2801,
    2803, 2819, 2833, 2837, 2843, 2851, 2857, 2861, 2879, 2887, 2897, 2903,
    2909, 2917, 2927, 2939, 2953, 2957, 2963, 2969, 2971, 2999, 3001, 3011,
    3019, 3023, 3037, 3041, 3049, 3061, 3067, 3079, 3083, 3089, 3109, 3119,
    3121, 3137, 3163, 3167, 3169, 3181, 3187, 3191, 3203, 3209, 3217, 3221,
    3229, 3251, 3253, 3257, 3259, 3271, 3299, 3301, 3307, 3313, 3319, 3323,
    3329, 3331, 3343, 3347, 3359, 3361, 3371, 3373, 3389, 3391, 3407, 3413,
    3433, 3449, 3457, 3461, 3463, 3467, 3469, 3491, 3499, 3511, 3517, 3527,
    3529, 3533, 3539, 3541, 3547, 3557, 3559, 3571, 3581, 3583, 3593, 3607,
    3613, 3617, 3623, 3631, 3637, 3643, 3659, 3671, 3673, 3677, 3691, 3697,
    3701, 3709, 3719, 3727, 3733, 3739, 3761, 3767, 3769, 3779, 3793, 3797,
    3803, 3821, 3823, 3833, 3847, 3851, 3853, 3863, 3877, 3881, 3889, 3907,
    3911, 3917, 3919, 3923, 3929, 3931, 3943, 3947, 3967, 3989, 4001, 4003,
    4007, 4013, 4019, 4021, 4027, 4049, 4051, 4057};
bool isPrime(int x) {
  if (binary_search(primes.begin(), primes.end(), x)) return 1;
  for (auto i : primes) {
    if (x % i == 0) return 0;
  }
  return 1;
}
int main() {
  int n;
  io >> n;
  vector<int> a(n);
  io >> a;
  int cnt1 = 0;
  vector<int> ta;
  for (auto i : a) {
    if (i == 1)
      cnt1++;
    else
      ta.emplace_back(i);
  }
  if (cnt1 >= 2) {
    for (auto i : ta) {
      if (isPrime(i + 1)) {
        io.WL(cnt1 + 1);
        while (cnt1--) io.WS(1);
        io.WL(i);
        return 0;
      }
    }
    io.WL(cnt1);
    while (cnt1--) io.WS(1);
    return 0;
  }
  if (cnt1 == 1)
    for (auto i : ta) {
      if (isPrime(i + 1)) {
        io.WL(2);
        while (cnt1--) io.WS(1);
        io.WL(i);
        return 0;
      }
    }
  for (int i = 0; i < ta.size(); i++)
    for (int j = i + 1; j < ta.size(); j++) {
      if (isPrime(ta[i] + ta[j])) {
        io.WL(2);
        io.WL(ta[i], ta[j]);
        return 0;
      }
    }
  io.WL(1);
  io.WL(a[0]);
  return 0;
}

### Prompt

In Cpp, your task is to solve the following problem:

A tuple of positive integers {x1, x2, ..., xk} is called simple if for all pairs of positive integers (i, j) (1 ≤ i < j ≤ k), xi + xj is a prime.

You are given an array a with n positive integers a1, a2, ..., an (not necessary distinct). You want to find a simple subset of the array a with the maximum size.

A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself.

Let's define a subset of the array a as a tuple that can be obtained from a by removing some (possibly all) elements of it.

Input

The first line contains integer n (1 ≤ n ≤ 1000) — the number of integers in the array a.

The second line contains n integers ai (1 ≤ ai ≤ 106) — the elements of the array a.

Output

On the first line print integer m — the maximum possible size of simple subset of a.

On the second line print m integers bl — the elements of the simple subset of the array a with the maximum size.

If there is more than one solution you can print any of them. You can print the elements of the subset in any order.

Examples

Input

2
2 3


Output

2
3 2


Input

2
2 2


Output

1
2


Input

3
2 1 1


Output

3
1 1 2


Input

2
83 14


Output

2
14 83

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
class IO {
  static const int bufSize = 1 << 18;
  char inBuf[bufSize], outBuf[bufSize];
  char *ip1 = inBuf, *ip2 = inBuf;
  int ok = 1, op1 = -1, op2 = bufSize - 1;
  template <typename T>
  __inline__ __attribute__((always_inline)) void __RI(T& x) {
    int ch = gc(), neg = 1;
    x = 0;
    for (; !(ch == EOF || isdigit(ch) || ch == '-'); ch = gc())
      ;
    if (ch == EOF) {
      ok = 0;
      return;
    }
    if (ch == '-') neg = -1, ch = gc();
    for (; isdigit(ch); ch = gc()) x = x * 10 + (ch - 48) * neg;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) void __RC(T& x) {
    unsigned char ch;
    while (isspace(ch = gc()))
      ;
    if (ch == EOF) {
      ok = 0;
      return;
    }
    x = ch;
  }
  __inline__ __attribute__((always_inline)) void __RS(string& x) {
    char ch;
    x.clear();
    for (ch = gc(); isspace(ch); ch = gc())
      ;
    if (ch == EOF) {
      ok = 0;
      return;
    }
    for (; !isspace(ch); ch = gc()) x.push_back(ch);
  }

 public:
  __inline__ __attribute__((always_inline)) int gc() {
    return ip1 == ip2 && (ip2 = (ip1 = inBuf) + fread(inBuf, 1, bufSize, stdin),
                          ip1 == ip2)
               ? EOF
               : *ip1++;
  }
  __inline__ __attribute__((always_inline)) IO& R(char& x) {
    __RC(x);
    return *this;
  }
  __inline__ __attribute__((always_inline)) IO& R(unsigned char& x) {
    __RC(x);
    return *this;
  }
  __inline__ __attribute__((always_inline)) IO& R(string& x) {
    __RS(x);
    return *this;
  }
  template <typename T1, typename T2>
  __inline__ __attribute__((always_inline)) IO& R(pair<T1, T2>& x) {
    R(x.first), R(x.second);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& R(vector<T>& x) {
    for (auto& i : x) R(i);
    return *this;
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& RA(T* a, int n) {
    for (int i = 0; i < n; ++i) R(a[i]);
    return *this;
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& R(T& x, Args&... args) {
    R(x), R(args...);
    return *this;
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& RA(T* a, int n, Args... args) {
    for (int i = 0; i < n; ++i) RA(a[i], args...);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& R(T& x) {
    static_assert(is_integral<T>::value, "Unsupported types");
    if (is_integral<T>::value) __RI(x);
    return *this;
  }

 private:
  char space = ' ';
  template <typename T>
  __inline__ __attribute__((always_inline)) void __WI(T x) {
    static char buf[64];
    static int len = -1;
    if (x >= 0) {
      do {
        buf[++len] = x % 10 + 48, x /= 10;
      } while (x);
    } else {
      pc('-');
      do {
        buf[++len] = -(x % 10) + 48, x /= 10;
      } while (x);
    }
    while (len >= 0) {
      pc(buf[len]), --len;
    }
  }

 public:
  __inline__ __attribute__((always_inline)) void pc(const char& x) {
    if (op1 == op2) flush();
    outBuf[++op1] = x;
  }
  __inline__ __attribute__((always_inline)) void flush() {
    fwrite(outBuf, 1, op1 + 1, stdout), op1 = -1;
  }
  __inline__ __attribute__((always_inline)) IO& W(const char& x) {
    pc(x);
    return *this;
  }
  __inline__ __attribute__((always_inline)) IO& W(const char* x) {
    while (*x != '\0') pc(*(x++));
    return *this;
  }
  __inline__ __attribute__((always_inline)) IO& W(const string& x) {
    W(x.c_str());
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& W(const vector<T>& x) {
    for (auto& i : x) WS(i);
    WL();
    return *this;
  }
  __inline__ __attribute__((always_inline)) IO& WL() {
    W('\n');
    return *this;
  }
  template <typename T1, typename T2>
  __inline__ __attribute__((always_inline)) IO& W(const pair<T1, T2>& x) {
    WS(x.first), W(x.second);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& WL(const T& x) {
    W(x), W('\n');
    return *this;
  }
  __inline__ __attribute__((always_inline)) IO& WS() {
    W(space);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& WS(const T& x) {
    W(x), W(space);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& WA(T* a, int n) {
    for (int i = 0; i < n; i++) WS(a[i]);
    WL();
    return *this;
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& W(const T& x,
                                                  const Args&... args) {
    W(x), W(space), W(args...);
    return *this;
  }
  template <typename... Args>
  __inline__ __attribute__((always_inline)) IO& WS(const Args&... args) {
    W(args...), W(space);
    return *this;
  }
  template <typename... Args>
  __inline__ __attribute__((always_inline)) IO& WL(const Args&... args) {
    W(args...), W('\n');
    return *this;
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& WA(T* a, int n, Args... args) {
    for (int i = 0; i < n; i++) WA(a[i], args...);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& W(const T& x) {
    static_assert(is_integral<T>::value, "Unsupported types");
    if (is_integral<T>::value) __WI(x);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& operator>>(T& x) {
    R(x);
    return *this;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& operator<<(const T& x) {
    W(x);
    return *this;
  }
  bool good() { return ok; }
  IO() {}
  ~IO() { flush(); }
} io;
const int32_t INF = 0x3f3f3f3f;
const int64_t INFL = 0x3f3f3f3f3f3f3f3fLL;
vector<int> primes = {
    2,    3,    5,    7,    11,   13,   17,   19,   23,   29,   31,   37,
    41,   43,   47,   53,   59,   61,   67,   71,   73,   79,   83,   89,
    97,   101,  103,  107,  109,  113,  127,  131,  137,  139,  149,  151,
    157,  163,  167,  173,  179,  181,  191,  193,  197,  199,  211,  223,
    227,  229,  233,  239,  241,  251,  257,  263,  269,  271,  277,  281,
    283,  293,  307,  311,  313,  317,  331,  337,  347,  349,  353,  359,
    367,  373,  379,  383,  389,  397,  401,  409,  419,  421,  431,  433,
    439,  443,  449,  457,  461,  463,  467,  479,  487,  491,  499,  503,
    509,  521,  523,  541,  547,  557,  563,  569,  571,  577,  587,  593,
    599,  601,  607,  613,  617,  619,  631,  641,  643,  647,  653,  659,
    661,  673,  677,  683,  691,  701,  709,  719,  727,  733,  739,  743,
    751,  757,  761,  769,  773,  787,  797,  809,  811,  821,  823,  827,
    829,  839,  853,  857,  859,  863,  877,  881,  883,  887,  907,  911,
    919,  929,  937,  941,  947,  953,  967,  971,  977,  983,  991,  997,
    1009, 1013, 1019, 1021, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069,
    1087, 1091, 1093, 1097, 1103, 1109, 1117, 1123, 1129, 1151, 1153, 1163,
    1171, 1181, 1187, 1193, 1201, 1213, 1217, 1223, 1229, 1231, 1237, 1249,
    1259, 1277, 1279, 1283, 1289, 1291, 1297, 1301, 1303, 1307, 1319, 1321,
    1327, 1361, 1367, 1373, 1381, 1399, 1409, 1423, 1427, 1429, 1433, 1439,
    1447, 1451, 1453, 1459, 1471, 1481, 1483, 1487, 1489, 1493, 1499, 1511,
    1523, 1531, 1543, 1549, 1553, 1559, 1567, 1571, 1579, 1583, 1597, 1601,
    1607, 1609, 1613, 1619, 1621, 1627, 1637, 1657, 1663, 1667, 1669, 1693,
    1697, 1699, 1709, 1721, 1723, 1733, 1741, 1747, 1753, 1759, 1777, 1783,
    1787, 1789, 1801, 1811, 1823, 1831, 1847, 1861, 1867, 1871, 1873, 1877,
    1879, 1889, 1901, 1907, 1913, 1931, 1933, 1949, 1951, 1973, 1979, 1987,
    1993, 1997, 1999, 2003, 2011, 2017, 2027, 2029, 2039, 2053, 2063, 2069,
    2081, 2083, 2087, 2089, 2099, 2111, 2113, 2129, 2131, 2137, 2141, 2143,
    2153, 2161, 2179, 2203, 2207, 2213, 2221, 2237, 2239, 2243, 2251, 2267,
    2269, 2273, 2281, 2287, 2293, 2297, 2309, 2311, 2333, 2339, 2341, 2347,
    2351, 2357, 2371, 2377, 2381, 2383, 2389, 2393, 2399, 2411, 2417, 2423,
    2437, 2441, 2447, 2459, 2467, 2473, 2477, 2503, 2521, 2531, 2539, 2543,
    2549, 2551, 2557, 2579, 2591, 2593, 2609, 2617, 2621, 2633, 2647, 2657,
    2659, 2663, 2671, 2677, 2683, 2687, 2689, 2693, 2699, 2707, 2711, 2713,
    2719, 2729, 2731, 2741, 2749, 2753, 2767, 2777, 2789, 2791, 2797, 2801,
    2803, 2819, 2833, 2837, 2843, 2851, 2857, 2861, 2879, 2887, 2897, 2903,
    2909, 2917, 2927, 2939, 2953, 2957, 2963, 2969, 2971, 2999, 3001, 3011,
    3019, 3023, 3037, 3041, 3049, 3061, 3067, 3079, 3083, 3089, 3109, 3119,
    3121, 3137, 3163, 3167, 3169, 3181, 3187, 3191, 3203, 3209, 3217, 3221,
    3229, 3251, 3253, 3257, 3259, 3271, 3299, 3301, 3307, 3313, 3319, 3323,
    3329, 3331, 3343, 3347, 3359, 3361, 3371, 3373, 3389, 3391, 3407, 3413,
    3433, 3449, 3457, 3461, 3463, 3467, 3469, 3491, 3499, 3511, 3517, 3527,
    3529, 3533, 3539, 3541, 3547, 3557, 3559, 3571, 3581, 3583, 3593, 3607,
    3613, 3617, 3623, 3631, 3637, 3643, 3659, 3671, 3673, 3677, 3691, 3697,
    3701, 3709, 3719, 3727, 3733, 3739, 3761, 3767, 3769, 3779, 3793, 3797,
    3803, 3821, 3823, 3833, 3847, 3851, 3853, 3863, 3877, 3881, 3889, 3907,
    3911, 3917, 3919, 3923, 3929, 3931, 3943, 3947, 3967, 3989, 4001, 4003,
    4007, 4013, 4019, 4021, 4027, 4049, 4051, 4057};
bool isPrime(int x) {
  if (binary_search(primes.begin(), primes.end(), x)) return 1;
  for (auto i : primes) {
    if (x % i == 0) return 0;
  }
  return 1;
}
int main() {
  int n;
  io >> n;
  vector<int> a(n);
  io >> a;
  int cnt1 = 0;
  vector<int> ta;
  for (auto i : a) {
    if (i == 1)
      cnt1++;
    else
      ta.emplace_back(i);
  }
  if (cnt1 >= 2) {
    for (auto i : ta) {
      if (isPrime(i + 1)) {
        io.WL(cnt1 + 1);
        while (cnt1--) io.WS(1);
        io.WL(i);
        return 0;
      }
    }
    io.WL(cnt1);
    while (cnt1--) io.WS(1);
    return 0;
  }
  if (cnt1 == 1)
    for (auto i : ta) {
      if (isPrime(i + 1)) {
        io.WL(2);
        while (cnt1--) io.WS(1);
        io.WL(i);
        return 0;
      }
    }
  for (int i = 0; i < ta.size(); i++)
    for (int j = i + 1; j < ta.size(); j++) {
      if (isPrime(ta[i] + ta[j])) {
        io.WL(2);
        io.WL(ta[i], ta[j]);
        return 0;
      }
    }
  io.WL(1);
  io.WL(a[0]);
  return 0;
}

```