​题目传送门​

#include <bits/stdc++.h>

using namespace std;

int main() {
int m, t, s;
cin >> m >> t >> s;
if(t==0) {
printf("0");
return 0;
}
int x = ceil(1.0 * s / t);
if (m <= x) printf("%d", 0);
else printf("%d", m - x);
return 0;
}