#include <stdio.h>

int main(){
    float p,r,n,emi,R=0;
    scanf("%f %f %f",&p,&r,&n);
    r = r/100;
    n = n/12;
    printf("%.2f",r)
    for(int i=0;i<n;i++){
        R += (1+r);
    }
    emi = (p*r*R)/(R-1);
    printf("%.2f",emi);
}