import fileinput as fi
IN = fi.input()

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

res=""
#print(line)
for i in range(1, len(line)):
    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(res))