def main():
    inp1, inp2 = map(int, input().split())
    time = [0] * inp2
    
    for i in range(inp1):
        inpx, inpy =map(int, input().split())
        for n in range(inpx, inpy + 1):
            time[n] = time[n] + 1
    print(max(time))
    
if __name__ == '__main__':
    main()