#include<bits/stdc++.h>
using namespace std;
int n,x,ans;
int y;
int main(){
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    cin>>n>>x>>y;
    for(int i=1;i<=y;i+=x) ans++;
    cout<<n-ans;
    return 0;}