C :

#include<stdio.h>
int main()
{
    long long a,b;
    while(scanf("%lld%lld",&a,&b)!=EOF)
    {
        if(a%2==0)
            a=a/2;
        else
            a=a/2+1;
        if(b<=a)
            b=b*2-1;
        else
            b=(b-a)*2;
        printf("%lld\n",b);
    }
    return 0;
}

C++ :

# include <iostream>
using namespace std;
long long n,k,s;
int main(){
	for ( ; cin >> n >> k ; cout << s << endl ) s = (k>(n+1)/2) ? ((k-(n+1)/2) * 2) : (k * 2 - 1);
	return 0;
}