#include<stdio.h>
#include<math.h>

int main(){
    double P,R;
    int N;
    
    scanf("%If%If%d",&P,&R,&N);
    
    if ( N == 0){
        printf("Invaild input");
        return 0;
    }
   double monthlyRate = R/(12*100);
   
   double emi=P* monthlRate*pow(1+montlyRate,N)/(pow(1+monthlyRate,N)-1);
   printf("%.2IF",emi);
   
   return 0;
    
}