MOD = 10**9 + 7

def parse_string(s):
    n = len(s)
    unknown = 0
    gold = []
    last_west = -1
    last_east = n
    for i in range(n):
        if s[i] == '<':
            last_west = i
        elif s[i] == '>':
            last_east = i
        elif s[i] == '