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