from sys import stdin, stdout


def main():
    n = stdin.readline()
    s = stdin.readline()
    sol = s[0]
    for i in range(1, len(s)):
        if s[i-1] == '(' and s[i] == ')':
            sol += "1"
            sol += s[i]
        elif s[i-1] == ')' and s[i] == ')':
            sol += "+1"
            sol += s[i]
        elif s[i-1] == ')' and s[i] == '(':
            sol += '*'
            sol += s[i]
        else:
            sol += s[i]
    
    print(eval(sol))
        

if __name__ == "__main__":
    main()