#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main()
{
    long long c=1,f;double a,b,d;
    scanf("%lf %lf %d",&a,&b,&f);
    double e;
    if(a==b)
        printf("%d",0);
    else
        {
         for(int i=1;i<=f;i++)
         c=c*10;
    e=c*a/b;
    c=c/10;
    d=c*a/b;
    printf("%d",(long long)e-(long long)d*10);

    }

    return 0;
}