__ + 4 = 17
4 + __ = 5
4 + __ = 12
__ + 4 = 6
__ + 1 = 13
5 + __ = 19
9 + __ = 15
__ + 6 = 20
5 + __ = 7
12 + __ = 13
9 + __ = 14
__ + 2 = 18
3 + __ = 16
6 + __ = 13
8 + __ = 16
__ + 2 = 10
4 + __ = 11
6 + __ = 16
__ + 11 = 15
11 + __ = 19
7 + __ = 18
__ + 1 = 16
11 + __ = 15
__ + 2 = 12
__ + 3 = 17
7 + __ = 12
__ + 6 = 19
1 + __ = 11
12 + __ = 16
__ + 2 = 3
13 + __ = 19
5 + __ = 10
2 + __ = 20
13 + __ = 20
14 + __ = 15
1 + __ = 8
2 + __ = 9
2 + __ = 3
__ + 6 = 8
__ + 7 = 16
__ + 13 = 16
2 + __ = 5
__ + 14 = 20
__ + 10 = 20
__ + 7 = 8
15 + __ = 18
6 + __ = 8
10 + __ = 13
11 + __ = 18
18 + __ = 19
3 + __ = 5
__ + 7 = 13
3 + __ = 20
5 + __ = 18
12 + __ = 20
4 + __ = 20