input:

17 17
6 10
1 9
14 6
12 13
5 4
15 17
14 15
6 5
10 6
10 11
2 9
9 6
17 15
9 15
4 8
1 4
13 15
13 19
11 10
12 10
10 5
2 8
12 11
8 3
1 7
10 9
8 5
1 5
9 4
8 7
12 10
6 8
13 1
5 8
11 5
10 8
7 7
16 14
9 5
8 1
4 16
10 8
16 15
15 1
13 5
9 3
4 4
9 7
7 2
5 4
5 11
9 14
5 13
1 5
4 5
4 1
4 4
1 1
5 3
3 5
4 1
3 2
5 1
...

output:

8
6
8
-5
1
-8
5
6
2
6
-7
8
10
10
10
10
1
6
11
8
10
10
6
13
7
7
2
0
2
6
3
2
12
4
-10
10
4
1
12
0
11
2
6
6
1
2
-11
3
7
7
8
6
-7
10
8
0
-4
8
1
4
-7
-11
1
8
8
-3
8
5
7
7
10
10
3
-13
3
7
-2
5
2
9
7
1
4
-1
2
1
10
4
3
10
4
6
7
4
7
3
1
2
6
7
6
4
-3
-9
-1
8
5
6
9
2
8
-7
4
10
10
10
1
-5
2
6
3
8
9
7
-7
6
1
-1
...

result:

wrong answer 4th lines differ - expected: '2', found: '-5'