Problem:
Score : 1000 points

Problem Statement

For an n \times n grid, let (r, c) denote the square at the (r+1)-th row from the top and the (c+1)-th column from the left.
A good coloring of this grid using K colors is a coloring that satisfies the following:

Each square is painted in one of the K colors.

Each of the K colors is used for some squares.

Let us number the K colors 1, 2, ..., K. For any colors i and j (1 \leq i \leq K, 1 \leq j \leq K), every square in Color i has the same number of adjacent squares in Color j. Here, the squares adjacent to square (r, c) are ((r-1)\; mod\; n, c), ((r+1)\; mod\; n, c), (r, (c-1)\; mod\; n) and (r, (c+1)\; mod\; n) (if the same square appears multiple times among these four, the square is counted that number of times).

Given K, choose n between 1 and 500 (inclusive) freely and construct a good coloring of an n \times n grid using K colors.
It can be proved that this is always possible under the constraints of this problem,

Constraints

1 \leq K \leq 1000

Input

Input is given from Standard Input in the following format:

K

Output

Output should be in the following format:

n
c_{0,0} c_{0,1} ... c_{0,n-1}
c_{1,0} c_{1,1} ... c_{1,n-1}
:
c_{n-1,0} c_{n-1,1} ... c_{n-1,n-1}

n should represent the size of the grid, and 1 \leq n \leq 500 must hold.
c_{r,c} should be an integer such that 1 \leq c_{r,c} \leq K and represent the color for the square (r, c).

Sample Input 1

2

Sample Output 1

3
1 1 1
1 1 1
2 2 2

Every square in Color 1 has three adjacent squares in Color 1 and one adjacent square in Color 2.

Every square in Color 2 has two adjacent squares in Color 1 and two adjacent squares in Color 2.

Output such as the following will be judged incorrect:

2
1 2
2 2

3
1 1 1
1 1 1
1 1 1

Sample Input 2

9

Sample Output 2

3
1 2 3
4 5 6
7 8 9

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <vector>
#include <algorithm>
#include <utility>
#include <set>
#include <map>
using namespace std;
#define REP(i, n) for(int i=0; i<(int)(n); i++)
typedef long long int lli;
const lli inf = 1e18;

int main(){
	lli l,n;
	cin >> l >> n;
	vector<lli> x(n);
	for(int i=0; i<n; i++) cin >> x[i];

	lli ans = 0;
	for(int d=0; d<2; d++){
		vector<lli> sum(n+1, 0);
		vector<lli> bsum(n+1, 0);
		for(int i=0; i<n; i++){
			sum[i+1] = sum[i]+x[i];
			}
		for(int i=n-1; i>=0; i--){
			bsum[i] = bsum[i+1]+(l-x[i]);
		}
		for(int i=0; i<n; i++){
			int m = n-i-1;
			lli sub = sum[i+(m+1)/2]-sum[i] +bsum[n-m/2];
			sub *= 2;
			if(m%2 == 0){
				sub += x[i+m/2];
			}else{
				sub += l-x[n-(m+1)/2];
			}
			ans = max(ans, sub);
		}
		for(int i=0; i<n; i++){
			x[i] = l-x[i];
		}
		reverse(x.begin(), x.end());
	}
	cout << ans << endl;
	return 0;
}