#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
istream &operator>>(istream &is, modint &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint &a) { return os << a.val(); }
istream &operator>>(istream &is, modint998244353 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint998244353 &a) { return os << a.val(); }
istream &operator>>(istream &is, modint1000000007 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint1000000007 &a) { return os << a.val(); } 

typedef long long ll;
typedef vector<vector<int>> Graph;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define FOR(i,l,r) for (int i = l;i < (int)(r); i++)
#define rep(i,n) for (int i = 0;i < (int)(n); i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define my_sort(x) sort(x.begin(), x.end())
#define my_max(x) *max_element(all(x))
#define my_min(x) *min_element(all(x))
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int INF = (1<<30) - 1;
const ll LINF = (1LL<<40) - 1;
const int MOD = 998244353;
const int MOD2 = 1e9+7;
const double PI = acos(-1);
vector<int> di = {1,0,-1,0};
vector<int> dj = {0,1,0,-1};

#ifdef LOCAL
#  include <debug_print.hpp>
#  define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define debug(...) (static_cast<void>(0))
#endif

using mint = modint998244353;
struct S{
    mint a, b, sum;
    int size;
};
using F = pair<mint, mint>;
S op(S lhs, S rhs){
    return {lhs.a + rhs.a, lhs.b + rhs.b, lhs.sum + rhs.sum, lhs.size + rhs.size};
}
S e(){ return {0, 0, 0, 0}; }
S mapping(F f, S x){
    return {x.a + f.first * x.size, x.b + f.second * x.size, x.sum + ((x.a * f.second) + (x.b * f.first)) + x.size * f.first * f.second, x.size};
}
F composition(F f, F g){
    return {f.first + g.first, f.second + g.second};
}
F id(){ return {0, 0}; } 

int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    int N; cin >> N;
    vector<ll> A(N + 1, LINF), B(N + 1, 0);
    rep(i, N){
        cin >> A[i];
        B[i] = A[i];
    }

    vector<S> dat(N + 1);
    rep(i, N + 1){
        dat[i].a = A[i];
        dat[i].b = B[i];
        dat[i].sum = A[i] * B[i];
        dat[i].size = 1;
    }
    lazy_segtree<S, op, e, F, mapping, composition, id> seg(dat);

    vector<int> stk_a = {N}, stk_b = {N};
    mint ans = 0;
    for(int i = N - 1; i >= 0; i--){

        while(A[stk_a.back()] < A[i]){
            int l = stk_a.back();
            stk_a.pop_back();
            int r = stk_a.back();
            seg.apply(l, r, F{A[i] - A[l], 0});
        }

        while(B[stk_b.back()] > B[i]){
            int l = stk_b.back();
            stk_b.pop_back();
            int r = stk_b.back();
            seg.apply(l, r, F{0, B[i] - B[l]});
        }

        ans += seg.prod(i, N).sum;

        // vector<mint> a(N), b(N), sum(N);
        // rep(j, N) {
        //     a[j] = seg.get(j).a;
        //     b[j] = seg.get(j).b;
        //     sum[j] = seg.get(j).sum;
        // }
        // debug(a, b, sum);

        stk_a.push_back(i);
        stk_b.push_back(i);
    }

    cout << ans << endl;
}