#include<stdio.h>
int main(){
    int usd_amounts;
    float conversions_rate = 0.85;
    scanf("%d",&usd_amount);
    if(usd_amount < 0){
        printf("Invali input\n");
    }else{
        float eur_amount = usd_amount * conversion_rate;
        printf("%.2f\n",eur_amount);
    }
    return 0;
}