S = input()
X = []
n = ''
for s in S:
    if s in '+*':
        X.append(int(n))
        X.append(s)
        n = ''
    else:
        n += s
else:
    X.append(int(n))

stack = [0]
for x in X:
    if stack[-1] == '+':
        stack.pop()
        stack.append(stack.pop() * x)

    elif stack[-1] == '*':
        stack.pop()
        stack.append(stack.pop() + x)

    else:
        stack.append(x)

print(stack[-1])