#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T sqr(T x) {
  return x * x;
}
template <class T>
inline T parse(const string &s) {
  T x;
  stringstream ss(s);
  ss >> x;
  return x;
}
const double EPS = 1e-12;
const int INF = 1000 * 1000 * 1000;
const long long LINF = INF * 1ll * INF;
const double DINF = 1e200;
const double PI = 3.1415926535897932384626433832795l;
int gcd(int a, int b) { return a ? gcd(b % a, a) : b; }
long long gcd(long long a, long long b) { return a ? gcd(b % a, a) : b; }
long long gcdex(long long a, long long b, long long &x, long long &y) {
  if (!a) {
    x = 0, y = 1;
    return b;
  }
  long long k = b / a;
  long long g = gcdex(b - k * a, a, y, x);
  x -= k * y;
  return g;
}
long long inv(long long a, long long m) {
  assert(m > 1);
  long long x, y, g;
  g = gcdex(a, m, x, y);
  return (x % (m / g) + m / g) % m / g;
}
long long crt(long long a1, long long m1, long long a2, long long m2) {
  long long a = (a2 - a1 % m2 + m2) % m2;
  long long x, y, g;
  g = gcdex(m1, m2, x, y);
  if (a % g) return -1;
  long long m = m1 / g * m2;
  assert(x + m2 >= 0);
  x = a / g * (x + m2) % m2;
  long long r = (a1 + x * m1) % m;
  assert(r % m1 == a1 && r % m2 == a2);
  return r;
}
long long powmod(long long a, long long p, long long m) {
  assert(p >= 0);
  long long r = 1;
  while (p) {
    if (p & 1) r = r * a % m;
    p >>= 1;
    a = a * a % m;
  }
  return r;
}
bool isprime(long long a) {
  if (a <= 1) return false;
  for (long long i = 2; i * i <= a; ++i) {
    if (a % i == 0) return false;
  }
  return true;
}
long long sqrtup(long long a) {
  if (!a) return 0;
  long long x = max(0ll, (long long)sqrt((double)a));
  while (x * x >= a) --x;
  while ((x + 1) * (x + 1) < a) ++x;
  return x + 1;
}
long long isqrt(long long a) {
  assert(a >= 0);
  long long x = max(0ll, (long long)sqrt((double)a));
  while (x * x > a) --x;
  while ((x + 1) * (x + 1) <= a) ++x;
  return x;
}
long long sgn(long long x) { return x < 0 ? -1 : x > 0 ? 1 : 0; }
template <class T>
ostream &operator<<(ostream &s, const vector<T> &v);
template <class A, class B>
ostream &operator<<(ostream &s, const pair<A, B> &p);
template <class K, class V>
ostream &operator<<(ostream &s, const map<K, V> &m);
template <class T>
ostream &operator<<(ostream &s, const set<T> &m);
template <class T, size_t N>
ostream &operator<<(ostream &s, const array<T, N> &a);
template <class... T>
ostream &operator<<(ostream &s, const tuple<T...> &t);
template <class T>
ostream &operator<<(ostream &s, const vector<T> &v) {
  s << '[';
  for (int i = 0; i < (((int)(v).size())); ++i) {
    if (i) s << ',';
    s << v[i];
  }
  s << ']';
  return s;
}
template <class A, class B>
ostream &operator<<(ostream &s, const pair<A, B> &p) {
  s << "(" << p.first << "," << p.second << ")";
  return s;
}
template <class K, class V>
ostream &operator<<(ostream &s, const map<K, V> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it.first << ": " << it.second;
  }
  s << "}";
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const set<T> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it;
  }
  s << "}";
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const multiset<T> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it;
  }
  s << "}";
  return s;
}
template <class T, class V, class C>
ostream &operator<<(ostream &s, const priority_queue<T, V, C> &q) {
  auto a = q;
  s << "{";
  bool f = false;
  while (!a.empty()) {
    if (f) s << ",";
    f = true;
    s << a.top();
    a.pop();
  }
  return s << "}";
}
template <class T, size_t N>
ostream &operator<<(ostream &s, const array<T, N> &a) {
  s << '[';
  for (int i = 0; i < (((int)(a).size())); ++i) {
    if (i) s << ',';
    s << a[i];
  }
  s << ']';
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const deque<T> &a) {
  s << '[';
  for (int i = 0; i < (((int)(a).size())); ++i) {
    if (i) s << ',';
    s << a[i];
  }
  s << ']';
  return s;
}
template <size_t n, class... T>
struct put1 {
  static ostream &put(ostream &s, const tuple<T...> &t) {
    s << get<sizeof...(T) - n>(t);
    if (n > 1) s << ',';
    return put1<n - 1, T...>::put(s, t);
  }
};
template <class... T>
struct put1<0, T...> {
  static ostream &put(ostream &s, const tuple<T...> &t) { return s; }
};
template <class... T>
ostream &operator<<(ostream &s, const tuple<T...> &t) {
  s << "(";
  put1<sizeof...(T), T...>::put(s, t);
  s << ")";
  return s;
}
ostream &put3(ostream &s, const char *, bool) { return s; }
template <class U, class... T>
ostream &put3(ostream &s, const char *f, bool fs, U &&u, T &&...t) {
  while (*f == ' ') ++f;
  if (!fs) s << ", ";
  auto nf = f;
  int d = 0;
  while (*nf && (*nf != ',' || d)) {
    if (*nf == '(')
      ++d;
    else if (*nf == ')')
      --d;
    ++nf;
  }
  auto nf2 = nf;
  while (nf2 > f && *(nf2 - 1) == ' ') --nf;
  fs = *f == '"';
  if (!fs) {
    s.write(f, nf2 - f);
    s << "=";
  };
  s << u;
  if (fs) s << ' ';
  if (*nf) ++nf;
  return put3(s, nf, fs, forward<T>(t)...);
}
int main(int argc, char **argv) {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.precision(20);
  srand(time(0));
  int n;
  cin >> n;
  struct bin {
    long long a = -INF * 10ll, b = INF * 10ll;
    vector<long long> rs, bs;
  };
  vector<bin> B(1);
  for (int i = 0; i < (n); ++i) {
    long long x;
    char c;
    cin >> x >> c;
    if (c == 'G') {
      B.back().b = x;
      B.emplace_back();
      B.back().a = x;
    } else
      (c == 'B' ? B.back().bs : B.back().rs).push_back(x);
  }
  long long ans = 0;
  for (const bin &b : B) {
    auto doit = [&ans](long long a, long long b,
                       const vector<long long> &v) -> long long {
      if (!((int)(v).size())) return b - a;
      if (a == -INF * 10ll && b == INF * 10ll) {
        ans += v.back() - v[0];
        return 0;
      }
      long long mxg = max(v[0] - a, b - v.back());
      for (int i = 0; i < (((int)(v).size()) - 1); ++i)
        mxg = max(mxg, v[i + 1] - v[i]);
      ans += b - a - mxg;
      return mxg;
    };
    long long g = doit(b.a, b.b, b.rs) + doit(b.a, b.b, b.bs);
    if (b.a == -INF * 10ll || b.b == INF * 10ll) continue;
    ans += min(g, b.b - b.a);
  }
  cout << ans;
  return 0;
}

### Prompt

Generate a cpp solution to the following problem:

Roy and Biv have a set of n points on the infinite number line.

Each point has one of 3 colors: red, green, or blue.

Roy and Biv would like to connect all the points with some edges. Edges can be drawn between any of the two of the given points. The cost of an edge is equal to the distance between the two points it connects.

They want to do this in such a way that they will both see that all the points are connected (either directly or indirectly).

However, there is a catch: Roy cannot see the color red and Biv cannot see the color blue.

Therefore, they have to choose the edges in such a way that if all the red points are removed, the remaining blue and green points are connected (and similarly, if all the blue points are removed, the remaining red and green points are connected).

Help them compute the minimum cost way to choose edges to satisfy the above constraints.

Input

The first line will contain an integer n (1 ≤ n ≤ 300 000), the number of points.

The next n lines will contain two tokens pi and ci (pi is an integer, 1 ≤ pi ≤ 109, ci is a uppercase English letter 'R', 'G' or 'B'), denoting the position of the i-th point and the color of the i-th point. 'R' means red, 'G' denotes green, and 'B' means blue. The positions will be in strictly increasing order.

Output

Print a single integer, the minimum cost way to solve the problem.

Examples

Input

4
1 G
5 R
10 B
15 G


Output

23


Input

4
1 G
2 R
3 B
10 G


Output

12

Note

In the first sample, it is optimal to draw edges between the points (1,2), (1,4), (3,4). These have costs 4, 14, 5, respectively.

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T sqr(T x) {
  return x * x;
}
template <class T>
inline T parse(const string &s) {
  T x;
  stringstream ss(s);
  ss >> x;
  return x;
}
const double EPS = 1e-12;
const int INF = 1000 * 1000 * 1000;
const long long LINF = INF * 1ll * INF;
const double DINF = 1e200;
const double PI = 3.1415926535897932384626433832795l;
int gcd(int a, int b) { return a ? gcd(b % a, a) : b; }
long long gcd(long long a, long long b) { return a ? gcd(b % a, a) : b; }
long long gcdex(long long a, long long b, long long &x, long long &y) {
  if (!a) {
    x = 0, y = 1;
    return b;
  }
  long long k = b / a;
  long long g = gcdex(b - k * a, a, y, x);
  x -= k * y;
  return g;
}
long long inv(long long a, long long m) {
  assert(m > 1);
  long long x, y, g;
  g = gcdex(a, m, x, y);
  return (x % (m / g) + m / g) % m / g;
}
long long crt(long long a1, long long m1, long long a2, long long m2) {
  long long a = (a2 - a1 % m2 + m2) % m2;
  long long x, y, g;
  g = gcdex(m1, m2, x, y);
  if (a % g) return -1;
  long long m = m1 / g * m2;
  assert(x + m2 >= 0);
  x = a / g * (x + m2) % m2;
  long long r = (a1 + x * m1) % m;
  assert(r % m1 == a1 && r % m2 == a2);
  return r;
}
long long powmod(long long a, long long p, long long m) {
  assert(p >= 0);
  long long r = 1;
  while (p) {
    if (p & 1) r = r * a % m;
    p >>= 1;
    a = a * a % m;
  }
  return r;
}
bool isprime(long long a) {
  if (a <= 1) return false;
  for (long long i = 2; i * i <= a; ++i) {
    if (a % i == 0) return false;
  }
  return true;
}
long long sqrtup(long long a) {
  if (!a) return 0;
  long long x = max(0ll, (long long)sqrt((double)a));
  while (x * x >= a) --x;
  while ((x + 1) * (x + 1) < a) ++x;
  return x + 1;
}
long long isqrt(long long a) {
  assert(a >= 0);
  long long x = max(0ll, (long long)sqrt((double)a));
  while (x * x > a) --x;
  while ((x + 1) * (x + 1) <= a) ++x;
  return x;
}
long long sgn(long long x) { return x < 0 ? -1 : x > 0 ? 1 : 0; }
template <class T>
ostream &operator<<(ostream &s, const vector<T> &v);
template <class A, class B>
ostream &operator<<(ostream &s, const pair<A, B> &p);
template <class K, class V>
ostream &operator<<(ostream &s, const map<K, V> &m);
template <class T>
ostream &operator<<(ostream &s, const set<T> &m);
template <class T, size_t N>
ostream &operator<<(ostream &s, const array<T, N> &a);
template <class... T>
ostream &operator<<(ostream &s, const tuple<T...> &t);
template <class T>
ostream &operator<<(ostream &s, const vector<T> &v) {
  s << '[';
  for (int i = 0; i < (((int)(v).size())); ++i) {
    if (i) s << ',';
    s << v[i];
  }
  s << ']';
  return s;
}
template <class A, class B>
ostream &operator<<(ostream &s, const pair<A, B> &p) {
  s << "(" << p.first << "," << p.second << ")";
  return s;
}
template <class K, class V>
ostream &operator<<(ostream &s, const map<K, V> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it.first << ": " << it.second;
  }
  s << "}";
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const set<T> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it;
  }
  s << "}";
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const multiset<T> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it;
  }
  s << "}";
  return s;
}
template <class T, class V, class C>
ostream &operator<<(ostream &s, const priority_queue<T, V, C> &q) {
  auto a = q;
  s << "{";
  bool f = false;
  while (!a.empty()) {
    if (f) s << ",";
    f = true;
    s << a.top();
    a.pop();
  }
  return s << "}";
}
template <class T, size_t N>
ostream &operator<<(ostream &s, const array<T, N> &a) {
  s << '[';
  for (int i = 0; i < (((int)(a).size())); ++i) {
    if (i) s << ',';
    s << a[i];
  }
  s << ']';
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const deque<T> &a) {
  s << '[';
  for (int i = 0; i < (((int)(a).size())); ++i) {
    if (i) s << ',';
    s << a[i];
  }
  s << ']';
  return s;
}
template <size_t n, class... T>
struct put1 {
  static ostream &put(ostream &s, const tuple<T...> &t) {
    s << get<sizeof...(T) - n>(t);
    if (n > 1) s << ',';
    return put1<n - 1, T...>::put(s, t);
  }
};
template <class... T>
struct put1<0, T...> {
  static ostream &put(ostream &s, const tuple<T...> &t) { return s; }
};
template <class... T>
ostream &operator<<(ostream &s, const tuple<T...> &t) {
  s << "(";
  put1<sizeof...(T), T...>::put(s, t);
  s << ")";
  return s;
}
ostream &put3(ostream &s, const char *, bool) { return s; }
template <class U, class... T>
ostream &put3(ostream &s, const char *f, bool fs, U &&u, T &&...t) {
  while (*f == ' ') ++f;
  if (!fs) s << ", ";
  auto nf = f;
  int d = 0;
  while (*nf && (*nf != ',' || d)) {
    if (*nf == '(')
      ++d;
    else if (*nf == ')')
      --d;
    ++nf;
  }
  auto nf2 = nf;
  while (nf2 > f && *(nf2 - 1) == ' ') --nf;
  fs = *f == '"';
  if (!fs) {
    s.write(f, nf2 - f);
    s << "=";
  };
  s << u;
  if (fs) s << ' ';
  if (*nf) ++nf;
  return put3(s, nf, fs, forward<T>(t)...);
}
int main(int argc, char **argv) {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.precision(20);
  srand(time(0));
  int n;
  cin >> n;
  struct bin {
    long long a = -INF * 10ll, b = INF * 10ll;
    vector<long long> rs, bs;
  };
  vector<bin> B(1);
  for (int i = 0; i < (n); ++i) {
    long long x;
    char c;
    cin >> x >> c;
    if (c == 'G') {
      B.back().b = x;
      B.emplace_back();
      B.back().a = x;
    } else
      (c == 'B' ? B.back().bs : B.back().rs).push_back(x);
  }
  long long ans = 0;
  for (const bin &b : B) {
    auto doit = [&ans](long long a, long long b,
                       const vector<long long> &v) -> long long {
      if (!((int)(v).size())) return b - a;
      if (a == -INF * 10ll && b == INF * 10ll) {
        ans += v.back() - v[0];
        return 0;
      }
      long long mxg = max(v[0] - a, b - v.back());
      for (int i = 0; i < (((int)(v).size()) - 1); ++i)
        mxg = max(mxg, v[i + 1] - v[i]);
      ans += b - a - mxg;
      return mxg;
    };
    long long g = doit(b.a, b.b, b.rs) + doit(b.a, b.b, b.bs);
    if (b.a == -INF * 10ll || b.b == INF * 10ll) continue;
    ans += min(g, b.b - b.a);
  }
  cout << ans;
  return 0;
}

```