'''
Math
Eat your heart out wolfram alpha
'''

ans = None

def error(type):
    print("Error", type + ":")
    if type == "UNMATCHED_BRACKET":
        print("\tFound an unclosed \"(\", cannot solve expression")
        return None
    elif type == "INVALID_TERM":
        print("\tExpresson contains invalid term that is neither an operator nor a number")
        return None
    else:
        print("\tMissing definition for error")

def solve(expr, explain = False):
    #doesn't ccount for negative terms

    global ans
    terms = expr.split(" ")
    for t in range(0, len(terms)):
        if terms[t] != "*" and terms[t] != "/" and terms[t] != "+" and terms[t] != "-" and terms[t] != "^":
            try:
                float(terms[t])
            except ValueError:
                return error("INVALID_TERM")
    for t in range(0, len(terms)):
        if terms[t] == "ans":
            terms[t] = ans
    for t in range(0, len(terms)):
        try:
            if terms[t] == "^":
                if explain:
                    print("\t" + str(float(terms[t-1]) ** float(terms[t+1])))
                terms.insert(t + 2,str(float(terms[t-1]) ** float(terms[t+1])))
                terms.pop(t+1)
                terms.pop(t)
                terms.pop(t-1)
        except IndexError:
            #due to popping, the for loop will go past the end of the list, so catch this and break the loop
            break
    for t in range(0, len(terms)):
        try:
            if terms[t] == "/":
                terms.pop(t-1)
                print("\t" + str(float(terms[t-1]) / float(terms[t+1])))
                terms.insert(t + 2,str(float(terms[t-1]) / float(terms[t+1])))
                terms.pop(t+1)
                terms.pop(t)
            elif terms[t] == "*":
                if explain:
                    print("\t" + str(float(terms[t-1]) * float(terms[t+1])))
                terms.insert(t + 2,str(float(terms[t-1]) * float(terms[t+1])))
                terms.pop(t+1)
                terms.pop(t)
                terms.pop(t-1)
        except IndexError:
            #due to popping, the for loop will go past the end of the list, so catch this and break the loop
            break
    for t in range(0, len(terms)):
        try:
            if terms[t] == "+":
                if explain:
                    print("\t" + str(float(terms[t-1]) + float(terms[t+1])))
                terms.insert(t + 2,str(float(terms[t-1]) + float(terms[t+1])))
                terms.pop(t+1)
                terms.pop(t)
                terms.pop(t-1)
            elif terms[t] == "-":
                if explain:
                    print("\t" + str(float(terms[t-1]) - float(terms[t+1])))
                terms.insert(t + 2,str(float(terms[t-1]) - float(terms[t+1])))
                terms.pop(t+1)
                terms.pop(t)
                terms.pop(t-1)
        except IndexError:
            #due to popping, the for loop will go past the end of the list, so catch this and break the loop
            break
    ans = "".join(terms)
    return "".join(terms)

def parse(expr, explain = False):
    if "(" in expr:
        open_bracket = expr.find("(")
        close_bracket = None
        ob = 0
        if ")" in expr:
            for c in range(open_bracket, len(expr)):
                if expr[c] == ")":
                    close_bracket = c
            if explain:
                print(expr, "\n" + " " * open_bracket + " ^")
            expr = expr.replace(expr[open_bracket:close_bracket+1], parse(expr[open_bracket + 1:close_bracket], explain), 1)
        else:
            return error("UNMATCHED_BRACKET")

    return solve(expr, explain)

def interperit():
    while True:
        command = input(">")
        if command == "":
            return None
        elif command[0] == "?":
            parse(command[1:], True)
        else:
            answer = parse(command)
            print(answer if answer != None else "")

interperit()