#include <stdio.h>
#include <algorithm>

using namespace std;

int main(void)
{
	double f;
	double a, b;
	int n, sum;
	
	while (scanf("%lf %lf %d", &a, &b, &n) != EOF){
		
		f = a / b;
		sum = 0;
		
		for (int i = 0; i < n; i++){
			while (f >= 1){
				f--;
			}
			f *= 10;
			sum = sum + f;
		}
		
		printf("%d\n", sum);
	}
	
	
	return (0);
}