#include <bits/stdc++.h>
using namespace std;
int main() {
  long n, m, k, t, i;
  pair<long, long> p;
  vector<long> hobbit;
  cin >> n >> m >> k;
  p.first = n;
  for (i = 1; i <= m; i++) {
    t = 1 + min(i, k - 1) + min(i, n - k);
    p.second = p.first;
    p.first += t;
    if (m > p.second && m <= p.first) break;
  }
  if (n == m)
    cout << 1;
  else
    cout << i + 1;
}
