N = int(raw_input())
tuples = []
for _ in xrange(N):
    v, t = map(int, raw_input().split())
    tuples.append(t * 20000 + v)

dp = [-1] * 10001
dp[0] = 0
tuples.sort()
for tuple_value in tuples:
    V = tuple_value % 20000
    T = tuple_value // 20000
    for n in xrange(T - 1, -1, -1):
        if dp[n] == -1:
            continue
        v = min(n + V, 10000)
        dp[v] = max(dp[v], dp[n] + V);

print max(dp)