n, b = map(int, input().split())
l, ans = [], 0
for i in range(n):
l.append([*map(int, input().split())])
l.sort(key=lambda t: t[0] + t[1])
for i in range(n):
bb = b - (l[i][0] / 2 + l[i][1])
cnt = 1 if bb >= 0 else 0
for j in range(n):
if j == i:
continue
if b < 0:
break
bb -= sum(l[j])
if bb >= 0:
cnt += 1
ans = max(ans, cnt)
print(ans)