input = """
2 18 3 0 3 19 20 21
1 1 1 0 18
2 23 3 0 3 19 24 25
1 1 2 1 21 23
3 5 21 19 20 24 25 0 0
6 0 5 5 21 19 20 24 25 1 1 1 1 1
0
21 a
19 b
20 c
24 d
25 e
28 f
0
B+
0
B-
1
0
1
"""
output = """
COST 1@1
"""

[]