#include<stdio.h>
int main(){
    
    int rectant1,reactant2,totalmass;
    scanf("%d" ,&reactant1);
    scanf("%d" ,&reactant2);
    if(rectant1<=1||reactant2<=1)
    {
        printf("Invalid input");
    }
    else{
        totalmass=reactant2+reactant2;
        printf("%d",totalmass);
    }
    return 0;
}