N=int(input())
X=[list(map(int,input().split())) for i in range(N)]
INF=10**15
DP=[[INF]*(N+1) for i in range(N+1)]
X.sort(key=lambda x:sum(x))
DP[0][0]=0
for i in range(N):
  for j in range(i+1):
    if DP[i][j]<=X[i][1]:
      DP[i+1][j+1]=min(DP[i+1][j+1],DP[i][j]+X[i][0])
    DP[i+1][j]=min(DP[i+1][j],DP[i][j])
for i in range(N,-1,-1):
  if DP[N][i]<INF:
    print(i)
    exit()