[Algorithm] 잃어버린 괄호

https://www.acmicpc.net/problem/1541

```Python3
formula = input().split('-')
arr = []

for i in formula:
    if '+' not in i:
        arr.append(int(i))
    else:
        temp = 0
        for j in i.split('+'):
            temp += int(j)
        arr.append(temp)

ans = arr.pop(0)
for i in arr:
    ans -= i

print(ans)
```