#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;
    }
    r=r/(12*100);
    
    
    double emi=(p*r*pow(1+rate,n))/(pow(1+rate,n)-1);
    // long double rounded=((long long)(emi*100.0L+0.5L)/100.0L);
    printf("%.2lf\n",emi);
    return 0;
    
}