n = int(input())
ws = [list(map(int, input().split())) for _ in range(n)]
ws.sort(key = lambda x:x[0] + x[1])

inf = 1 << 60
dp = [0]
for w, s in ws:
    dp += [inf]
    l = len(dp)
    for i in range(l - 1, 0, -1):
        if dp[i - 1] <= s:
            dp[i] = min(dp[i], dp[i - 1] + w)
            
dp += [inf]
for i in range(1, len(dp)):
    if dp[i] == inf:
        print(i - 1)
        exit()