找规律
#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>
#include <cmath>
using namespace std;
int n,k;
int main()
{
int ans;
scanf("%d%d",&n,&k);
if(n==1)
{
ans=1;
}
else
{
ans=min(k,n-k+1)*2;
}
printf("%d\n",ans);
return 0;
}