#include #include #include using namespace std; int main(){ int n, m; cin >> n >> m; vector w(m, 0); vector> vp; for(int i = 0; i < n; i++){ int x, y; cin >> x >> y; vp.push_back({x, y}); } sort(vp.begin(), vp.end()); for(int i = 0; i < n; i++){ int l = vp[i].first, r = vp[i].second; bool ok = true; for(int j = l; j <= r; j++) ok &= !w[j]; if(ok){ for(int j = l; j <= r; j++) w[j] = true; continue; } ok = true; for(int j = l; j <= r; j++) ok &= !w[m-1-j]; if(ok){ for(int j = l; j <= r; j++) w[m-1-j] = true; continue; } cout << "NO" << endl; return 0; } cout << "YES" << endl; return 0; }