#include <bits/stdc++.h>
using namespace std;
int main() {
int n, x, y;
    cin >> n >> x >> y;
    int e;
    if (x == 0) {
        e = 0;
    } else {
        e = (y + x - 1) / x;
    }
    
    int ans = n - e;
    if (ans < 0) ans = 0;
    
    cout << ans << endl;
    return 0;
}