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