int N,M,A[1d5+1],I[1d5]={},ans[1d5];
VI E[1d5],V;

{
	rd(N,M,A(N)--);
	rep(i,N-2) if(A[i]==A[i+2]) wt("No"),exit(0);
	rep(i,N-1){
		if(i%2){ E[A[i+1]].push_back(A[i]); I[A[i]]++; }
		else{ E[A[i]].push_back(A[i+1]); I[A[i+1]]++; }
	}
	queue<int> Q; rep(i,M) if(I[i]==0) Q.push(i);
	while(Q.size()){
		int p=Q.front(); Q.pop();
		V.push_back(p);
		for(int e:E[p]) if(0==--I[e]) Q.push(e);
	}
	if(V.size()!=M) wt("No"),exit(0);
	wt("Yes");
	rep(i,M) ans[V[i]]=i+1;
	wt(ans(M));
}