There are n psychos standing in a line. Each psycho is assigned a unique integer from 1 to n. At each step every psycho who has an id greater than the psycho to his right (if exists) kills his right neighbor in the line. Note that a psycho might kill and get killed at the same step. 

You're given the initial arrangement of the psychos in the line. Calculate how many steps are needed to the moment of time such, that nobody kills his neighbor after that moment. Look notes to understand the statement more precise.

Input

The first line of input contains integer n denoting the number of psychos, (1 ≤ n ≤ 105). In the second line there will be a list of n space separated distinct integers each in range 1 to n, inclusive — ids of the psychos in the line from left to right.

Output

Print the number of steps, so that the line remains the same afterward.

Examples

Input

10
10 9 7 8 6 5 3 4 2 1


Output

2


Input

6
1 2 3 4 5 6


Output

0

Note

In the first sample line of the psychos transforms as follows: [10 9 7 8 6 5 3 4 2 1]  →  [10 8 4] →  [10]. So, there are two steps.
#include <bits/stdc++.h>
using namespace std;
template <class _T>
inline _T sqr(const _T &first) {
  return first * first;
}
template <class _T>
inline string tostr(const _T &a) {
  ostringstream os("");
  os << a;
  return os.str();
}
const long double PI = 3.1415926535897932384626433832795L;
const long double EPS = 1e-7;
char TEMPORARY_CHAR;
const int INF = 1e9;
inline void fft(vector<complex<double> > &a, bool invert) {
  int n = (int)a.size();
  for (int i = 1, j = 0; i < n; ++i) {
    int bit = n >> 1;
    for (; j >= bit; bit >>= 1) j -= bit;
    j += bit;
    if (i < j) swap(a[i], a[j]);
  }
  for (int len = 2; len <= n; len <<= 1) {
    long double ang = 2 * PI / len * (invert ? -1 : 1);
    complex<double> wlen(cos(ang), sin(ang));
    for (int i = 0; i < n; i += len) {
      complex<double> w(1);
      for (int j = 0; j < len / 2; ++j) {
        complex<double> u = a[i + j], v = a[i + j + len / 2] * w;
        a[i + j] = u + v;
        a[i + j + len / 2] = u - v;
        w *= wlen;
      }
    }
  }
  if (invert)
    for (int i = 0; i < n; ++i) a[i] /= n;
}
inline void input(int &a) {
  a = 0;
  while (((TEMPORARY_CHAR = getchar()) > '9' || TEMPORARY_CHAR < '0') &&
         (TEMPORARY_CHAR != '-')) {
  }
  char neg = 0;
  if (TEMPORARY_CHAR == '-') {
    neg = 1;
    TEMPORARY_CHAR = getchar();
  }
  while (TEMPORARY_CHAR <= '9' && TEMPORARY_CHAR >= '0') {
    a = (a << 3) + (a << 1) + TEMPORARY_CHAR - '0';
    TEMPORARY_CHAR = getchar();
  }
  if (neg) a = -a;
}
inline void out(long long a) {
  if (!a) putchar('0');
  if (a < 0) {
    putchar('-');
    a = -a;
  }
  char s[20];
  int i;
  for (i = 0; a; ++i) {
    s[i] = '0' + a % 10;
    a /= 10;
  }
  for (int j = (i)-1; j >= 0; j--) putchar(s[j]);
}
inline int nxt() {
  int(ret);
  input((ret));
  ;
  return ret;
}
struct lnum {
  vector<int> a;
  int base;
  lnum(int num = 0, int base = 1000000000) : base(base) {
    if (!num) a.resize(1);
    while (num) {
      a.push_back(num % base);
      num /= base;
    }
  }
  inline int len() const { return a.size(); }
  lnum &operator=(const lnum &l) {
    if (this != &l) {
      a = l.a;
      base = l.base;
    }
    return *this;
  }
  inline friend lnum operator+(const lnum &l, const lnum &r) {
    lnum ret(0, l.base);
    int base = l.base;
    int ln = l.len(), rn = r.len();
    int n = max(ln, rn);
    ret.a.resize(n);
    int o = 0;
    for (int i = 0; i < n; ++i) {
      int s = o;
      if (i < ln) s += l.a[i];
      if (i < rn) s += r.a[i];
      o = s >= base;
      if (o) s -= base;
      ret.a[i] = s;
    }
    if (o) ret.a.push_back(1);
    return ret;
  }
  inline friend lnum operator-(const lnum &l, const lnum &r) {
    lnum ret(0, l.base);
    int base = l.base;
    int n = l.len();
    int rn = r.len();
    ret.a.resize(n);
    int o = 0;
    for (int i = 0; i < n; ++i) {
      int s = l.a[i] - o;
      if (i < rn) s -= r.a[i];
      o = s < 0;
      if (o) s += base;
      ret.a[i] = s;
    }
    if (ret.len() > 1 && !ret.a.back()) ret.a.pop_back();
    return ret;
  }
  inline friend lnum operator*(const lnum &l, const lnum &r) {
    lnum ret(0, l.base);
    int base = l.base;
    if (l.len() * r.len() > 1000000) {
      vector<complex<double> > fa(l.a.begin(), l.a.end()),
          fb(r.a.begin(), r.a.end());
      int n = 1;
      while (n < max(l.len(), r.len())) n <<= 1;
      n <<= 1;
      fa.resize(n), fb.resize(n);
      fft(fa, false), fft(fb, false);
      for (int i = 0; i < n; ++i) fa[i] *= fb[i];
      fft(fa, true);
      ret.a.resize(n);
      for (int i = 0; i < n; ++i) ret.a[i] = int(fa[i].real() + 0.5);
      int carry = 0;
      for (int i = 0; i < n; ++i) {
        ret.a[i] += carry;
        carry = ret.a[i] / base;
        ret.a[i] %= base;
      }
      while (!ret.a.back() && ret.a.size() > 1) ret.a.pop_back();
    } else {
      ret.a.resize(l.len() + r.len());
      for (int i = 0; i < l.len(); ++i)
        for (int j = 0, carry = 0; j < r.len() || carry; ++j) {
          long long cur = ret.a[i + j] +
                          (long long)l.a[i] * (j < r.len() ? r.a[j] : 0) +
                          carry;
          ret.a[i + j] = cur % base;
          carry = cur / base;
        }
    }
    while (ret.len() > 1 && !ret.a.back()) ret.a.pop_back();
    return ret;
  }
  inline friend lnum operator/(const lnum &l, const int &r) {
    lnum ret(0, l.base);
    ret.a.resize(l.len());
    int carry = 0;
    for (int i = l.len() - 1; i >= 0; --i) {
      long long cur = l.a[i] + (long long)carry * l.base;
      ret.a[i] = cur / r;
      carry = cur % r;
    }
    while (ret.len() > 1 && ret.a.back() == 0) ret.a.pop_back();
    return ret;
  }
  inline friend bool operator<(const lnum &l, const lnum &r) {
    if (l.len() < r.len()) return true;
    if (l.len() > r.len()) return false;
    int n = l.len();
    for (int i = n - 1; i >= 0; --i) {
      if (l.a[i] < r.a[i]) return true;
      if (l.a[i] > r.a[i]) return false;
    }
    return false;
  }
  inline friend bool operator>(const lnum &l, const lnum &r) { return r < l; }
  inline friend bool operator==(const lnum &l, const lnum &r) {
    if (l.len() != r.len()) return false;
    int n = l.len();
    for (int i = n - 1; i; --i) {
      if (l.a[i] != r.a[i]) return false;
    }
    return true;
  }
  inline friend bool operator!=(const lnum &l, const lnum &r) {
    return !(l == r);
  }
  inline void print() {
    if (base == 1000000000) {
      printf("%d", a.back());
      for (int i = a.size() - 2; i >= 0; --i) printf("%09d", a[i]);
    } else {
      for (int i = a.size() - 1; i >= 0; --i) printf("%d", a[i]);
    }
  }
};
inline int *arr(int n) {
  int *ret = new int[n];
  for (int i = 0; i < (int)(n); i++) ret[i] = nxt();
  return ret;
}
int solve(vector<int> z) {
  int ans = 0;
  while (1) {
    vector<int> t;
    t.push_back(z[0]);
    for (int i = 1; i < z.size(); ++i)
      if (z[i] > z[i - 1]) t.push_back(z[i]);
    if (t.size() == z.size()) break;
    ++ans;
    z = t;
  }
  return ans;
}
int main() {
  int(n);
  input((n));
  ;
  list<int> a;
  list<int>::iterator q[n];
  for (int i = 0; i < (int)(n); i++) {
    int z = nxt() - 1;
    q[z] = a.insert(a.end(), z);
  }
  int time = 0;
  int tt[n];
  memset((tt), 0, sizeof(tt));
  for (int i = 0; i < (int)(n); i++) {
    auto p = q[i];
    if (p == a.end()) continue;
    ++p;
    while (p != a.end()) {
      if (*p > i) break;
      tt[i] = max(tt[i] + 1, tt[*p]);
      p = a.erase(p);
    }
    ((time) = (tt[i]) > (time) ? (tt[i]) : (time));
  }
  cout << time << endl;
  return 0;
}
