import sys
input = sys.stdin.readline

N = int(input())
D = []
for i in range(N):
    w, s = map(int, input().split())
    D.append((s*(s + w), w, s))

D.sort()
inf = 10 ** 18
dp = [inf] * (N + 1)
dp[0] = 0
for i in range(N):
    for j in range(N -1, -1, -1):
        if D[i][2] >= dp[j]:
            dp[j + 1] = min(dp[j + 1], dp[j] + D[i][1])

ans = -1
for i in range(N + 1):
    if dp[i] != inf:
        ans = i

print(ans)