#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using mint = atcoder::modint998244353;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, k, v;
    cin >> n >> k;
    mint p0 = 1, p1 = 1, coef = 1;
    for(int i = 0; i < n; i++){
        cin >> v;
        if(v < k) continue;
        coef *= mint::raw(v).inv();
        p0 *= mint::raw(k);
        p1 *= mint::raw(k - 1);
    }
    cout << ((p0 - p1) * coef).val() << '\n';
}