import fileinput as fi
IN = fi.input()

a = int(IN.readline())
line = IN.readline()
for _ in range(1000000):
   line = line.replace(")(", ")*(").replace("()", "(1)").replace("))", ")+1)")

# res=""
# #print(line)
# for i in range(1, a):
#     if line[i-1] == ")" and line[i] == "(":
#         res += "+"
#     elif line[i-1] == "(" and line[i] == ")":
#         res += "1"
#     elif line[i-1] == ")" and line[i] == ")":
#         res += "+1"

#print(res)
print(eval(line))