import copy

def main():
    N = int(input()); INF = float("inf")
    Z = []
    for i in range(N):
        w,s = map(int,input().split())
        Z.append((w,s))
    Z.sort(key = lambda x: x[0] + x[1])
    #dp[i][j]: i個目まで見てj個使った時の最小の重さ
    dp = [INF]*(N+1)
    dp[0] = 0
    for i in range(N):
        p = copy.copy(dp) #i個目を使わないときをコピー
        p,dp = dp,p
        w,s = Z[i]
        for j in range(N):
            if dp[j] <= s:
                dp[j+1] = min(dp[j+1], p[j] + w)
    #print(dp)
    for j in reversed(range(N+1)):
        if dp[j] != INF:
            print(j);exit()

if __name__ == '__main__':
    main()