#include <bits/stdc++.h>
using namespace std;
long long n, m, p, total = 1;
int main() {
  cin >> n >> m >> p;
  m -= n;
  long long nexr = 0;
  long long nexl = 0;
  while (m > 0) {
    if (nexr + nexl + 1 > m) break;
    m -= (nexr + nexl + 1);
    total++;
    if (nexl + nexr + 1 == n) {
      total += m / n;
      break;
    }
    if (p - 1 > nexl) nexl++;
    if (n - p > nexr) nexr++;
  }
  cout << total;
  return 0;
}
