Untitled

def rec_sum(s,coin):
    if s==0:
        print("Finish")
        return True
    if s<0 : return False
    for _ in coin:
        if rec_sum(s - _, coin):
            return True
    return False

if __name__ == '__main__':
    coin = set([7,3])
    print(rec_sum(11,coin))