#include<stdio.h>
#include<math.h>
int main(){
    double P,R;
    int N;
    scanf("%lf %lf %d", &P, &R, &N);
    if(N<=0){
        printf("Invalid input");
        return 0;
    }
    if(P<=0||R<=0||N<=0){
        printf("Invalid input");
        return 0;
    }
    double R=R/(12*100);
    double EMI;
    EMI=(P*R*(1+R,N))/((1+R,N)-1);
    printf("%.2lf",EMI);
    return 0;
}