Độ khó: Khá (3/4 điểm)

Sample Input 1

2 2
BW
WB
WB
BW

Sample Output 1

YES
1
1 1

Sample Input 2

2 3
BWB
WBW
BBB
WWW

Sample Output 2

NO

Sample Input 3

3 3
WWW
BWW
WWB
WBB
WWB
BBB

Sample Output 3

YES
2
1 2
2 1

Độ khó: Khá (3/4 điểm)

Sample Input 1

7 3
1 9 6 10 2 3 5
1 5
3 6
4 7

Sample Output 1

5
3
1

Sample Input 2

6 2
2 1 2 2 1 1
1 3
2 6

Sample Output 2

1
3

Độ khó: Khá (3/4 điểm)

Sample Input

5 6
1 3
2 4 3
3 5 1 2
1 2
1 3
1
2
3
4
5
6

Sample Output

3
1
3
2
3
5