#include <iostream>
#include <cstdlib>
#include <cmath>
using namespace std;

int main()
{
    double a,b,c;
    scanf("%lf%lf%lf",&a,&b,&c);
    double ans = a/b;
    for(int i=0;i<c;i++)
     {
         ans*=10;
     }

    int transform = ans+0.5;
    ans = double(transform)/10;
    for(int i=1;i<c;i++)
     {
         ans/=10;
     }
    printf("%lf\n",ans);
   return 0;
}