import std.algorithm, std.conv, std.range, std.stdio, std.string;

void main()
{
  auto rd1 = readln.split.to!(size_t[]), n = rd1[0], m = rd1[1];

  auto g = new bool[][](n, m);
  foreach (i; 0..n) {
    auto rd2 = readln.split.to!(size_t[]), l = rd2[0], r = rd2[1] + 1;
    foreach (j; l..r) g[i][j] = true;
  }

  auto ci = new int[](m);
  foreach (i; 0..m)
    ci[i] = g.transversal(i).count!"a".to!int;

  if (m % 2 && ci[m/2+1] >= 2) {
    writeln("NO");
    return;
  }

  foreach (i; 0..m/2)
    if (ci[i] + ci[$-i-1] >= 3) {
      writeln("NO");
      return;
    }

  writeln("YES");
}