#include<bits/stdc++.h> using namespace std; int m,s,t; int main(){ cin>>m>>t>>s; if(t0) { cout<<0<<endl; return 0; } if(s%t0) cout<<max( m-s/t , 0)<<endl; else cout<<max( m-s/t-1 , 0)<<endl; return 0; }