#include<stdio.h>
#include<math.h>
int main(){
    double p,r,n;
    if(scanf(%lf %lf %lf,&p,&r,&n)!=3){
        printf("Invalid input");
        return 0;
    }
    if(n==0){
        printf("Invalid input");
        return 0;
    }
    double monthlyrate=r/(12*100);
    double numerator=p*monthlyrate*pow(1+monthlyrate,n);
    double denominator=pow(1+monthlyrate,n)-1;
    double emi=0;
    if(denominator!=0)
        emi=numerator/denominator;
    printf("%.21f ",emi);
    return 0;
}