import sys
input = sys.stdin.readline
N = int(input())
a = [tuple(map(int, input().split())) for _ in range(N)]
a.sort(key = lambda x: (x[1], x[0]))
inf = 10 ** 9 * N
dp = [inf] * (N + 1)
dp[0] = 0
for i in range(N):
  w, s = a[i]
  for i in range(N - 1, -1, -1):
    if dp[i] <= s: dp[i + 1] = min(dp[i + 1], dp[i] + w)
for i in range(N, -1, -1):
  if dp[i] < inf:
    print(i)
    break