#include<stdio.h>
union Distance { float km,float mi;};
int main(){
    int choice;
    float distance;
    union Distance d;
    scanf("%d %f",&choice,&distance);
    if(choice==1 && distace>=0){
        d.km=distance;
        printf("%.2f\n",d.km*0.621371);
    } else if(choice==2 && distance>=0){
        d.mi=distance;
        printf("%.2f\n",d.mi/0.621371);
    } else {
        printf("Invalid input");
    }
    return 0;
}