344A. Candy Bags

A. Candy Bags

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

Gerald has n younger brothers and their number happens to be even. One day he bought n2 candy bags. One bag has one candy, one bag has two candies, one bag has three candies and so on. In fact, for each integer k from 1 to n2 he has exactly one bag with kcandies.

Help him give n bags of candies to each brother so that all brothers got the same number of candies.

Input

The single line contains a single integer n (n is even, 2 ≤ n ≤ 100) — the number of Gerald's brothers.

Output

Let's assume that Gerald indexes his brothers with numbers from 1 to n. You need to print n lines, on the i-th line print n integers — the numbers of candies in the bags for the i-th brother. Naturally, all these numbers should be distinct and be within limits from 1 to n2. You can print the numbers in the lines in any order.

It is guaranteed that the solution exists at the given limits.

Sample test(s)

input

2

output

1 42 3

Note

The sample shows Gerald's actions if he has two brothers. In this case, his bags contain 1, 2, 3 and 4 candies. He can give the bags with 1 and 4 candies to one brother and the bags with 2 and 3 to the other brother.

题目本身很水，然而我又一次栽在审题上，没看见它说n是偶数，奇数情况想了半天。

审题要认真！！

将背包按顺序分为n个一组，从两边开始往中间输出就行。

#include <iostream>using namespace std;int main(void){int n;cin>>n;for(int i=1 ; i<=n ; ++i){bool first=1;for(int j=i ; j<=n/2*n ; j+=n)if(first){cout<<j;first=0;}else cout<<" "<<j;for(int j=n*n-i+1 ; j>=n/2*n+1 ; j-=n)cout<<" "<<j;cout<<"\n";}return 0;}