YES
28
1 1
1 2
1 1
1 3
1 2
1 1
1 4
1 3
1 2
1 1
1 5
1 4
1 3
1 2
1 1
1 6
1 5
1 4
1 3
1 2
1 1
1 7
1 6
1 5
1 4
1 3
1 2
1 1
