n = int(input())
ws = [list(map(int, input().split())) for _ in range(n)]

ws.sort(key=lambda x: x[0] + x[1])

dp = [[1 << 60] * (n + 1) for _ in range(n + 1)]
dp[0][0] = 0

for t in range(n):
    w, s = ws[t]
    dp[t + 1][0] = 0
    for i in range(n, 0, -1):
        if dp[t][i - 1] <= s:
            dp[t + 1][i] = min(dp[t][i], dp[t][i - 1] + w)
        else:
            dp[t + 1][i] = dp[t][i]

for i in range(n, 0, -1):
    if dp[n][i] != 1 << 60:
        print(i)
        break