#include<iostream>
#include<string>
#include<vector>
#include<cstdio>
#include<cmath>

using namespace std;

int main()
{
  float a, b;
  int n, c;
  vector<int> nums;
  while(cin >> a >> b >> n){
    float j = a / b;
    for(int i = 0; i < n; i++)
    {
      j *= 10;
      c = floor(j);
      //cout << c % 10 << endl;
      nums.push_back(c % 10);
    }
    int ans = 0;
    for(int i = 0; i < n; i++)
    {
      //cout << nums[i] << endl;
      ans += nums[i];
    }
    cout << ans << endl;
    nums.clear();
  }
}