#include <bits/stdc++.h>
using namespace std;
int n, m, k, dr, st, i, p;
int main() {
  cin >> n >> m >> k;
  if (n == 1)
    cout << m;
  else if (n == m)
    cout << "1";
  else {
    p = m - n;
    i = 1;
    dr = k;
    st = k;
    while (p > 0) {
      if (dr - st + 1 <= p) {
        i++;
        p -= dr - st + 1;
        if (dr < n) dr++;
        if (st > 1) st--;
      } else
        p -= p;
    }
    cout << i;
  }
  return 0;
}
