import java.util.*; import java.io.*; import java.awt.geom.*; import java.math.*; public class No0274 { static final Scanner in = new Scanner(System.in); static final PrintWriter out = new PrintWriter(System.out,false); static void solve() { int n = in.nextInt(); int m = in.nextInt(); int[] cnt = new int[m]; for (int i=0; i 2) { out.println("NO"); return; } } out.println("YES"); } public static void main(String[] args) { long start = System.currentTimeMillis(); solve(); out.flush(); long end = System.currentTimeMillis(); //trace(end-start + "ms"); in.close(); out.close(); } static void trace(Object... o) { System.out.println(Arrays.deepToString(o));} }