#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, k;
  int ans = 0;
  while (~scanf("%d%d%d", &n, &m, &k)) {
    ans = 0;
    m -= n;
    ans++;
    int x = 0;
    int y = 0;
    if (m) {
      ans++;
      m--;
    }
    while (m) {
      bool xx = 0;
      bool yy = 0;
      if (x + k < n) {
        x++;
      } else
        xx = 1;
      if (k - y > 1) {
        y++;
      } else
        yy = 1;
      m -= x;
      m -= y;
      if (m <= 0) break;
      if (m) {
        ans++;
        m--;
      }
      if (m <= 0) break;
      if (xx && yy) {
        ans += m / (x + y + 1);
        break;
      }
    }
    printf("%d\n", ans);
  }
}
