def get_id(c):
if c == "(":
return 1
elif c == "[":
return 2
elif c == "]":
return 3
elif c == ")":
return 4
return 0
def main():
string = input()
s = []
flag = True
for c in string:
id = get_id(c)
if id > 2:
if not s or s[-1] + id != 5:
flag = False
break
else:
s.pop()
elif id > 0:
s.append(id)
if flag and not s:
print("true")
else:
print("false")
if __name__ == "__main__":
main()



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