#!/usr/bin/env python3

lines = (x.strip() for x in open("input.txt"))
signals, x, pos = 0, 1, 0

for line in lines:
    is_add = line[0] == 'a'
    for _ in range(1 + is_add):
        pos += 1
        signals += pos * x if pos % 40 == 20 else 0
    x += int(line[5:]) if is_add else 0

print(signals)