#include <bits/stdc++.h>

using namespace std;
using ll = long long;

const int mod = 998244353;

int main(){
    int N;
    cin >> N;
    int a[N];
    for(int i = 0;i < N;++i)
        cin >> a[i];
    ll ans = 1;
    for(int i = 0;i + 1 < N;++i){
        ans = ans * min(a[i], a[i + 1]) % mod;
    }
    cout << ans << endl;
    return 0;
}