import sys

input = sys.stdin.buffer.readline


N, H = map(int, input().split())
streams = []
for _ in range(N):
    A, B = map(int, input().split())
    streams.append(A * 2)
    streams.append(B * 2 + 1)

streams.sort()
watching = 0
ans = 0
for stream in streams:
    time, is_end = divmod(stream, 2)
    if is_end:
        watching -= 1
    else:
        watching += 1
    ans = max(ans, watching)
print(ans)