s = input()

ans = 0
now_num, k = get_number(s, 0)
ans = now_num
while k < len(s):
    sign = s[k]
    k += 1
    now_num, k = get_number(s, k)
    if sign == '+':
        ans += now_num
    else:
        ans -= now_num

print(ans)