#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint998244353;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  VI a(n);
  rep(i, n) cin >> a[i], a[i]--;
  mint ans;
  rep(i, n) ans += m - (a[i] + 1);
  ans *= mint(m).pow(n - 1);
  ans += mint(m).pow(n);
  vector<P> lr(n + 1);
  for (int i = 1; i < n; i++) {
    lr[i] = {min(a[i-1], a[i]) + 1, max(a[i-1], a[i]) + 1};
  }
  vector<array<int, 6>> ps(n);
  rep(i, n) {
    ps[i][1] = lr[i].first;
    ps[i][2] = lr[i].second;
    ps[i][3] = lr[i+1].first;
    ps[i][4] = lr[i+1].second;
    ps[i][5] = m;
    ranges::sort(ps[i]);
  }
  array<mint, 5> dp;
  auto is_between = [&](int x, P rng) {
    return rng.first <= x && x < rng.second;
  };
  rep(j, 5) dp[j] = ps[0][j+1] - ps[0][j];
  for (int i = 1; i < n; i++) {
    array<mint, 5> ndp;
    rep(j, 5) rep(k, 5) {
      if ((a[i-1] > a[i] && is_between(ps[i-1][j], lr[i]) && !is_between(ps[i][k], lr[i])) ||
          (a[i-1] < a[i] && is_between(ps[i][k], lr[i]) && !is_between(ps[i-1][j], lr[i]))) {
        continue;
      }
      ndp[k] += dp[j] * (ps[i][k+1] - ps[i][k]);
    }
    dp = ndp;
  }
  mint bad = accumulate(all(dp), mint());
  ans -= bad;
  cout << ans.val() << '\n';
}