552E - Vanya and Brackets - CodeForces Solution

expr = list(input())
mul_pos = [-1]
add_cnt = [0] * len(expr)
for i, _ in enumerate(expr):
    add_cnt[i] = add_cnt[i - 1]      if _ == '*':
        mul_pos.append(i)
    elif _ == '+':
        add_cnt[i] += 1
mul_pos.append(len(expr))
add_cnt.append(add_cnt[-1])
add_cnt.append(0)
ans = 0
for i in range(len(mul_pos)):
    for j in range(i + 1, len(mul_pos)):
        if add_cnt[mul_pos[i]] - add_cnt[mul_pos[j]]:
            expr.insert(mul_pos[i] + 1, '(')
            expr.insert(mul_pos[j] + 1, ')')
                        ans = max(ans, eval(''.join(expr)))
            expr.pop(mul_pos[j] + 1)
            expr.pop(mul_pos[i] + 1)
print(eval(''.join(expr)) if ans == 0 else ans)