import sys
input = sys.stdin.readline
from operator import itemgetter

N=int(input())
W=[tuple(map(int,input().split())) for i in range(N)]

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

DP=[1<<60]*(N+1)
DP[0]=0

for w,s in W:
    for i in range(N,-1,-1):
        if DP[i]==1<<60:
            continue
        if DP[i]<=s:
            DP[i+1]=min(DP[i+1],DP[i]+w)

ANS=0
for i in range(N+1):
    if DP[i]!=1<<60:
        ANS=i
print(ANS)