According to rules of the Berland fashion, a jacket should be fastened by all the buttons except only one, but not necessarily it should be the last one. Also if the jacket has only one button, it should be fastened, so the jacket will not swinging open.

You are given a jacket with n buttons. Determine if it is fastened in a right way.

Input

The first line contains integer n (1 ≤ n ≤ 1000) — the number of buttons on the jacket.

The second line contains n integers ai (0 ≤ ai ≤ 1). The number ai = 0 if the i-th button is not fastened. Otherwise ai = 1.

Output

In the only line print the word "YES" if the jacket is fastened in a right way. Otherwise print the word "NO".

Examples

Input

3
1 0 1


Output

YES


Input

3
1 0 0


Output

NO
import java.util.*;
import java.io.*;
public class FashioninBerland
{


    /************************ SOLUTION STARTS HERE ***********************/



    private static void solve(FastScanner s1, PrintWriter out){

	int n = s1.nextInt();
	int arr[] = s1.nextIntArray(n);

	if(n == 1)
	    out.println(arr[0] == 1 ? "YES" : "NO");
	else{
	    int cnt = 0;
	    for(int fuckers:arr)
		cnt += 1 - fuckers;

	    if(cnt == 1)
		out.println("YES");
	    else 
		out.println("NO");
	}
    }



    /************************ SOLUTION ENDS HERE ************************/





    /************************ TEMPLATE STARTS HERE *********************/

    public static void main(String []args) throws IOException {
	FastScanner in  = new FastScanner(System.in);
	PrintWriter out = 
		new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)), false); 
	solve(in, out);
	in.close();
	out.close();
    }    

    static class FastScanner{
	BufferedReader reader;
	StringTokenizer st;
	FastScanner(InputStream stream){reader=new BufferedReader(new InputStreamReader(stream));st=null;}	
	String next()
	{while(st == null || !st.hasMoreTokens()){try{String line = reader.readLine();if(line == null){return null;}		    
	st = new StringTokenizer(line);}catch (Exception e){throw new RuntimeException();}}return st.nextToken();}
	String nextLine()  {String s=null;try{s=reader.readLine();}catch(IOException e){e.printStackTrace();}return s;}	    	  	
	int    nextInt()   {return Integer.parseInt(next());}
	long   nextLong()  {return Long.parseLong(next());}		
	double nextDouble(){return Double.parseDouble(next());}
	char   nextChar()  {return next().charAt(0);}
	int[]  nextIntArray(int n)         {int[] arr= new int[n];   int i=0;while(i<n){arr[i++]=nextInt();}  return arr;}
	long[] nextLongArray(int n)        {long[]arr= new long[n];  int i=0;while(i<n){arr[i++]=nextLong();} return arr;}	
	int[]  nextIntArrayOneBased(int n) {int[] arr= new int[n+1]; int i=1;while(i<=n){arr[i++]=nextInt();} return arr;}	    	
	long[] nextLongArrayOneBased(int n){long[]arr= new long[n+1];int i=1;while(i<=n){arr[i++]=nextLong();}return arr;}	    	
	void   close(){try{reader.close();}catch(IOException e){e.printStackTrace();}}				
    }

    /************************ TEMPLATE ENDS HERE ************************/
}