package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
)

func solve(in io.Reader, out, err io.Writer) {
	sum, num, answer := float64(0), 0, float64(0)
	fmt.Fscan(in, &num, &answer)
	for temp, i := float64(0), 0; i < num; i++ {
		fmt.Fscan(in, &temp)
		sum += temp
	}

	if answer != sum/float64(num) {
		fmt.Fprintln(out, "NO")
	} else {
		fmt.Fprintln(out, "YES")
	}
}

func main() {
	br := bufio.NewReaderSize(os.Stdin, int(1e7))
	solve(br, os.Stdout, os.Stderr)
}