题目链接：codeforces.com/problemset/problem/1136/B

题目分析

    首先，读完题目，看了是个B题，嗯嗯......

    果断找规律，然后交了一波，居然过了！！！

代码区

#include
    
     #include
     
      #include
      
       #include
       
        #include 
        
         using namespace std;typedef long long ll;const int inf = 0x3f3f3f3f;const int Max = 5e2 + 10;const int mod = 1e9 + 7;int main(){	int n, k;	while (scanf("%d%d", &n, &k) != EOF)	{		int a = min(abs(k - 1), abs(n - k));		printf("%d\n", 3 * n +  a);	}	return 0;}