import sys

def solve():
    a, b, c = map(int, input().split())
    flag1 = False
    flag2 = False

    if a + b == c:
        flag1 = True
    if a - b == c:
        flag2 = True

    if flag1 and flag2:
        print('?')
    elif flag1:
        print('+')
    elif flag2:
        print('-')
    else:
        print('!')

if __name__ == '__main__':
    solve()