#include <bits/stdc++.h>
using namespace std;
int main(){
  int N, M;
  cin >> N >> M;
  vector<int> a(N);
  for (int i = 0; i < N; i++){
    cin >> a[i];
    a[i]--;
  }
  bool ok = true;
  for (int i = 0; i < N - 2; i++){
    if (a[i] == a[i + 2]){
      ok = false;
    }
  }
  if (!ok){
    cout << "No" << endl;
  } else {
    vector<vector<int>> E(M);
    for (int i = 0; i < N - 1; i++){
      if (i % 2 == 0){
        E[a[i]].push_back(a[i + 1]);
      } else {
        E[a[i + 1]].push_back(a[i]);
      }
    }
    vector<int> d(M, 0);
    for (int i = 0; i < M; i++){
      for (int j : E[i]){
        d[j]++;
      }
    }
    queue<int> Q;
    for (int i = 0; i < M; i++){
      if (d[i] == 0){
        Q.push(i);
      }
    }
    int cnt = 0;
    vector<int> ans(M, -1);
    while (!Q.empty()){
      int v = Q.front();
      Q.pop();
      cnt++;
      ans[v] = cnt;
      for (int w : E[v]){
        d[w]--;
        if (d[w] == 0){
          Q.push(w);
        }
      }
    }
    for (int i = 0; i < M; i++){
      if (ans[i] == -1){
        ok = false;
      }
    }
    if (!ok){
      cout << "No" << endl;
    } else {
      cout << "Yes" << endl;
      for (int i = 0; i < M; i++){
        cout << ans[i] << endl;
      }
    }
  }
}