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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import java.util.NoSuchElementException;

public class Main {
	static FastScanner sc;
	static int H;
	static int W;
	static List<Integer> resList = new ArrayList<>();
	public static void main(String[] args){
		sc = new FastScanner();
		solve();
	}

	static void solve(){
		H = sc.nextInt();
		W = sc.nextInt();
		int HW = H*W;
		PrintWriter out = new PrintWriter(System.out);
		boolean[] matMap = new boolean[HW+1];
		boolean revFlg = false;
		for(int i=1;i<=HW;i++){
			if(!revFlg){
				matMap[i] = sc.nextInt()%2==0;
			}else{
				int tmp = i - 1;
				int l = (tmp/W+1)*W - (tmp%W);
				matMap[l] = sc.nextInt()%2==0;
			}
			if(i%W==0){
				revFlg = !revFlg;
			}
		}
		int count =0;
		for(int i=1;i<=HW;i++){
			if(!matMap[i] && i!=HW){
				getLine(i);
				matMap[i+1] = !matMap[i+1];
				count++;
			}
		}
		out.println(count);
		for(int i=0;i<resList.size();i++){
			if(i%4==3){
				out.println(resList.get(i));
			}else {
				out.print(resList.get(i));
				out.print(" ");
			}
		}
		out.flush();
		return;
	}
	static void getLine(int i){
		i--;
		int div = i/W;
		int mod = i%W;
		boolean revFlg = div%2==1;
		if(!revFlg){
			resList.add(div+1);
			resList.add(mod+1);
			if(mod+1==W){
				resList.add(div+2);
				resList.add(mod+1);
			}else{
				resList.add(div+1);
				resList.add(mod+2);
			}
		}else{
			int tmp = (div+1)*W-mod -1;
			mod = tmp%W;
			resList.add(div+1);
			resList.add(mod+1);
			if(mod==0){
				resList.add(div+2);
				resList.add(mod+1);
			}else{
				resList.add(div+1);
				resList.add(mod);
			}
		}

	}
}

class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }
    private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
    private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
    public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble() { return Double.parseDouble(next());}
}