#include <iostream>
#include <cmath>
using namespace std;
int main(){
  double a,b,n;
  int sum,s,p;
  cin >> a >> b >> n 
    sum = 0;
  for(int i = 1 ; i <= n ; i++){

    s = (a/b)*pow(10,i);
    sum += s%10;
  }
  cout << sum << endl;
  return 0;
}