#include<stdio.h>
#include<math.h>
int main(){
    double p,r;
    int n;
    if(scanf("%lf %lf %d",&p,&r,&n) !=3)
    {
        printf("Invalid input");
        return 0;
        
    }
    if( n==0 ){
        printf("Invalid input");
        return 0;
    }
    r=r/(12*100);
    double ratepower=pow(1+r,n);
    double EMI;
        if(r==0)
            EMI = p/n;
        else
            EMI =(p * r *ratepower)/(ratepower -1);
            
            EMI= float(EMI * 100)/100;
            
    printf("%.2lf",EMI); 
    return 0;
}