#include <iostream>
using namespace std;
int main(){
    int m,t,s;
    cin>>m>>t>>s;
    int qwe;
    double a;
    if(t!=0 && m!=0){
        a=s/t;
        a=m-a;
    }
    if(t<=0 || m<=0){
        cout<<"0"<<endl;
    }
    else{
        cout<<a<<endl;
    }
}

40 求大佬看看哪错了