MAX = 101
INF = 1000000000

prev = [-INF] * MAX
next = [-INF] * MAX
next[0] = 0
t = price = 0

with open("in.csv") as f:
    for line in f:
        splitted = line.split(',')

        try:
            t = int(splitted[0])
            price = int(splitted[1])
        except:
            continue
        if t == 100:
            break

        for i in xrange(MAX):
            prev[i] = next[i]



        for i in xrange(MAX):
            if prev[i] == -INF:
                continue
            if i < MAX - 1:
                next[i + 1] = max(next[i + 1], prev[i] - price)
            if i > 0:
                next[i - 1] = max(next[i - 1], prev[i] + price)

result = -INF
for i in xrange(MAX):
    next[i] += i * price
    result = max(next[i], result)
print result