import java.io.*;
import java.util.*;
import java.util.stream.*;

// 処理
class Process {
    private int   a;
    private int[] x;

    Process(int a, int[] x) {
        this.a = a;
        this.x = x;
    }

    String getResult() {
        double average = 0.0;
        for(var i : x) {
            average += i;
        }
        average /= x.length;

        return ((average == a) ? "YES" : "NO");
    }
}

public class Main {
    public static void main(String[] args) throws IOException {
        var bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        var printWriter    = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));

        // 入力
        int[] input = Stream.of(bufferedReader.readLine().trim().split("[ ]+")).mapToInt(Integer::parseInt).toArray();

        int[] x = Stream.of(bufferedReader.readLine().trim().split("[ ]+")).mapToInt(Integer::parseInt).toArray();

        // 出力
        printWriter.println((new Process(input[1], x)).getResult());

        bufferedReader.close();
        printWriter.close();
    }
}