#include <bits/stdc++.h>
 #define int long long
 #define endl '\n'
 using namespace std;
 signed main(){
 int n,x,y,chi;
 cin>>n>>x>>y;
 if(y%x!=0){
 chi=y/x+1; }
 else if(y%x==0){ 
 chi=y/x; }
 cout<<n-chi;
 return 0;
 }