// macros
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <vector>
#include <string>
#include <map>

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;

#define LLINF 1000000000000000000LL
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define debug(a) cout << "L(" << __LINE__ << "):" << #a << ":" << a << endl;

// problems limits
#define MAX_N 10

// Variables
ll n, a;
ll X[MAX_N];

// problems input
void input()
{
    cin >> n >> a; 
    FOR(i,0,n) cin >> X[i];
}

// problems main
void solve()
{
    ll sum=0;
    FOR(i,0,n) sum+=X[i];
    if(a*n==sum) {
        cout << "YES"<< endl;
    } else {
        cout << "NO" << endl;
    }
}

int main()
{
    ios::sync_with_stdio(false);

    input();

    solve();
}