#define _USE_MATH_DEFINES
#define INF 0x3f3f3f3f
#include <cstdio>
#include <iostream>
#include <sstream>
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <stack>
#include <limits>
#include <map>
#include <string>
#include <cstring>
#include <set>
#include <deque>
#include <bitset>
#include <list>
#include <cctype>
#include <utility>

using namespace std;

typedef long long ll;
typedef pair <int,int> P;
typedef pair <int,P > PP;

int tx[] = {0,1,0,-1};
int ty[] = {-1,0,1,0};

static const double EPS = 1e-8;

int main(){

	int a,b,n;
	while(~scanf("%d %d %d",&a,&b,&n)){
		double num = (double)a/(double)b;
		int sum = 0;
		for(int i=1;i<=n;i++){
			num *= 10;
			ll tmp = (ll)num;
			sum += tmp % 10;
			num -= tmp;
		}

		printf("%d\n",sum);
	}
}