#include<cstdio>
#include<stdlib.h>
#include<iostream>
#include<sstream>
using namespace std;
int main(){
        double X,Y,N;
        char num[100]={0};
        while(scanf("%lf%lf%lf",&X,&Y,&N)!=EOF){
                int FLG=0,total=0,cnt=0;
                char W;
                sprintf(num,"%.15lf",X/Y);
                for(int i=0;;i++){
                        if(FLG==1){
                                W=num[i];
                                total+=atoi(&W);
                                cnt++;
                        }
                        if(cnt==N)break;
                        if(num[i]=='.')FLG=1;
                }
                printf("%d\n",total);
        }
        return 0;
}