#include <bits/stdc++.h>

using namespace std;

int main()
{
    double a,b,n;
    cin>>a>>b>>n;
if(a==b){
cout<<0;
return 0;}
    double c=1.0*a/b;
    double d=1.0*c*pow(10,n);

    cout<<(long long)d%10;
        }