#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, k, rm, fr = 1, l, r, li = 0, ri = 0, c = 0;
  cin >> n >> m >> k;
  if (n == 1) {
    cout << m << endl;
    return 0;
  }
  l = k - 1;
  r = n - k;
  rm = m - n;
  while (1) {
    if (c + li + ri + 1 <= rm) {
      c += (li + ri + 1);
      fr++;
    } else
      break;
    if (l > li) li++;
    if (r > ri) ri++;
  }
  cout << fr << endl;
}
