#!/usr/bin/python3

n = int(input())

exams = [[int(x) for x in input().split()] for _ in range(n)]

# dp[i][j] is: 
#   the max amount of unallocated prep time at the end of exam i - 1, after passing j exams, or
#   -1 if it is not possible to pass j exams at the end of exam i - 1.
# (exam -1 means the time 0)
dp = [[-1]*(n+1) for _ in range(n+1)]

dp[0][0] = 0

for i in range(1, n+1):
    dp[i][0] = dp[i-1][0] + exams[i-1][0] - (exams[i-2][2] if (i - 2 >= 0) else 0)


for i in range(1, n+1):
    for j in range(1, n+1):
        if dp[i-1][j] != -1:
            dp[i][j] = dp[i-1][j] + (exams[i-1][0] - (exams[i-2][2] if (i - 2 >= 0) else 0))
        if dp[i-1][j-1] >= 0 and dp[i-1][j-1] + (exams[i-1][0] - (exams[i-2][2] if i - 2 >= 0 else 0)) >= exams[i-1][3]:
            dp[i][j] = max(dp[i][j], 
                    dp[i-1][j-1] + (exams[i-1][0] - (exams[i-2][2] if i - 2 >= 0 else 0)) - exams[i-1][3] + 
                        exams[i-1][2] - exams[i-1][1])

print(max(j for j in range(n+1) if dp[-1][j] >= 0))