#include<stdio.h>
int main(){
    double usd_amount;
    if(scanf("%lf", &usd_amount) != 1){
        return 1;
        
    }    
    if(usd_amount < 0){
        printf("Invalid input\n");
    }    
    else{
        double euro_amount = usd_amount * EURO_PER_USD;
    printf("%.2lf\n", euro_amount);
    }
    return 0;
}