30
0 a 3
0 b 0
1 a 23
1 b 8
2 a 7
2 b 7
3 a 4
3 b 23
4 a 3
4 b 21
5 a 23
5 b 28
6 a 17
6 b 2
7 a 18
7 b 13
8 a 1
8 b 0
9 a 2
9 b 6
10 a 7
10 b 16
11 a 19
11 b 0
12 a 17
12 b 6
13 a 22
13 b 20
14 a 22
14 b 17
15 a 13
15 b 7
16 a 14
16 b 18
17 a 8
17 b 25
18 a 27
18 b 0
19 a 24
19 b 25
20 a 5
20 b 22
21 a 13
21 b 10
22 a 8
22 b 4
23 a 6
23 b 24
24 a 10
24 b 3
25 a 2
25 b 12
26 a 3
26 b 11
27 a 27
27 b 11
28 a 19
28 b 8
29 a 25
29 b 1
23 14
20
1
2
3
6
7
9
11
12
13
14
17
18
19
20
22
24
25
26
28
29