Problem:
Score : 400 points

Problem Statement

There is a grid of square cells with H horizontal rows and W vertical columns. The cell at the i-th row and the j-th column will be denoted as Cell (i, j).

In Cell (i, j), a_{ij} coins are placed.

You can perform the following operation any number of times:

Operation: Choose a cell that was not chosen before and contains one or more coins, then move one of those coins to a vertically or horizontally adjacent cell.

Maximize the number of cells containing an even number of coins.

Constraints

All values in input are integers.

1 \leq H, W \leq 500

0 \leq a_{ij} \leq 9

Input

Input is given from Standard Input in the following format:

H W
a_{11} a_{12} ... a_{1W}
a_{21} a_{22} ... a_{2W}
:
a_{H1} a_{H2} ... a_{HW}

Output

Print a sequence of operations that maximizes the number of cells containing an even number of coins, in the following format:

N
y_1 x_1 y_1' x_1'
y_2 x_2 y_2' x_2'
:
y_N x_N y_N' x_N'

That is, in the first line, print an integer N between 0 and H \times W (inclusive), representing the number of operations.

In the (i+1)-th line (1 \leq i \leq N), print four integers y_i, x_i, y_i' and x_i' (1 \leq y_i, y_i' \leq H and 1 \leq x_i, x_i' \leq W), representing the i-th operation. These four integers represents the operation of moving one of the coins placed in Cell (y_i, x_i) to a vertically or horizontally adjacent cell, (y_i', x_i').

Note that if the specified operation violates the specification in the problem statement or the output format is invalid, it will result in Wrong Answer.

Sample Input 1

2 3
1 2 3
0 1 1

Sample Output 1

3
2 2 2 3
1 1 1 2
1 3 1 2

Every cell contains an even number of coins after the following sequence of operations:

Move the coin in Cell (2, 2) to Cell (2, 3).

Move the coin in Cell (1, 1) to Cell (1, 2).

Move one of the coins in Cell (1, 3) to Cell (1, 2).

Sample Input 2

3 2
1 0
2 1
1 0

Sample Output 2

3
1 1 1 2
1 2 2 2
3 1 3 2

Sample Input 3

1 5
9 9 9 9 9

Sample Output 3

2
1 1 1 2
1 3 1 4

Solution in Python (3.4.3) (judge verdict: Wrong Answer)

import numpy as np
H, W = map(int, input().split())

lst = [list(map(int, input().split())) for _ in range(H)]
dp = np.array(lst)


def check(i, j):
    if dp[i][j] % 2 == 0:
        return True
    else:
        return False

flag = True #True: 右向き探索、False: 左向き探索
h = 0 #縦
w = 0 #横
ans = [] #操作を残しておくリスト
count = 0 #操作の回数
for i in range(H*W): #最大回数試す
    # print (i-1, '(h, w) =', h, w)
    # print (dp)
    if check(h, w): #既に偶数
        if flag == True and w == W - 1:
            flag = not flag
            h += 1
        elif flag == False and w == 0:
            flag = not flag
            h += 1
        elif flag == True:
            w += 1
        elif flag == False:
            w -= 1
        continue
    else: #奇数の時、1つ次にずらす
        if i == (H*W-1): #最後の一回は奇数だとしても動かすところがない
        # if h == H - 1 and w == W - 1 and flag == True: #右下のマスで右に行け = 全探索終了
            continue
        else:
            count += 1
            if flag: #flag == True: 右向き探索
                if w == W - 1: #右向き探索で既に一番右の時
                    #下に移す
                    dp[h][w] -= 1
                    dp[h + 1][w] += 1
                    ans += [[h+1, w+1, h+2, w+1]]
                    flag = not flag #探索の向きを変える
                    h += 1 #下段に移る
                else: #右に移す場所がある時
                    dp[h][w] -= 1
                    dp[h][w + 1] += 1
                    ans += [[h+1, w+1, h+1, w+2]]
                    w += 1
            else: #左向き探索
                if w == 0: #左向き探索で既に一番左の時
                    #下に移す
                    dp[h][w] -= 1
                    dp[h+1][w] += 1
                    ans += [[h+1, w+1, h+2, w+1]]
                    flag = not flag
                    h += 1
                else: #左に移す場所がある時
                    dp[h][w] -= 1
                    dp[h][w - 1] += 1
                    ans += [[h+1, w+1, h, w+1]]
                    w -= 1

# print (count)
# print ('ans', np.array(ans))
# print ('dp', dp)

# 以下答えの出力部分
print (count) #操作回数の出力
for i in ans: #ansのリストを全走査
    print (i[0], i[1], i[2], i[3])
    # for j in i:
    #     print (j, end = ' ')
    # print ()