#include <iostream>
#include <vector>
#include <atcoder/convolution>
#include <atcoder/modint>
#include <cassert>

using namespace std;
using namespace atcoder;
using mint = modint998244353;

using ll = long long;
const int MX = 200010;
mint f[MX],inv[MX],fi[MX];
constexpr ll mod = 998244353;
void solve(){
    inv[1] = 1;
    for(int i=2;i<MX;i++){
        inv[i] = mod - (mod/i)*inv[mod%i];
    }
    f[0] = fi[0] = 1;
    for(int i=1;i<MX;i++){
        f[i] = f[i-1]*i;
        fi[i] = fi[i-1]*inv[i];
    }
}

int main(){
    solve();
    int i,n; cin >> n;
    vector<ll> a(n + 1);
    for(i=0;i<n;i++) cin >> a[i];
    reverse(a.begin(),a.end());
    // vector<ll> sum(n + 2);
    // for(i=1;i<n + 2;i++) sum[i] += sum[i - 1] + a[i - 1];
    vector<mint> dp(n + 1);
    dp[0] = 1;
    // [l,r)
    auto rec = [&](int l,int r,auto &self){
        if(r==l + 1) return;
        int mid = lower_bound(a.begin() + l,a.end(),(a[l] + a[r - 1])/2) - a.begin();
        if(mid==r) mid--;
        if(mid==l) mid++;
        // cout << l << " " << mid << " " << r << endl;
        // assert(l<=mid);
        // assert(mid<=r);
        self(l,mid,self);
        const int b1 = a[l];
        const int b2 = a[mid] - a[mid - 1];
        vector<mint> ff(a[mid - 1] + 1 - b1),gg(a[r - 1] - a[l] + 1 - b2);
        for(i=l;i<mid;i++) ff[a[i] - b1] += dp[i];
        for(i=a[mid] - a[mid - 1];i<=a[r - 1] - a[l];i++) gg[i - b2] = fi[i];
        vector<mint> hh = convolution(ff,gg); 
        for(i=mid;i<r;i++){
            if(hh.size()>a[i] - b1 - b2) dp[i] += hh[a[i] - b1 - b2];
        }
        self(mid,r,self);
    };
    rec(0,n + 1,rec);
    for(i=0;i<=n;i++) dp[i] *= f[a[i]];
    mint ans = 0;
    for(i=1;i<=n;i++) ans += dp[i];
    cout << ans.val() << "\n";

    // deb
    // vector<mint> dp2(n + 1);
    // dp2[0] = 1;
    // for(i=1;i<=n;i++){
    //     for(int j=0;j<i;j++) dp2[i] += dp2[j]*fi[a[i] - a[j]];
    // }
    // for(i=0;i<=n;i++) cout << dp[i].val() << " ";
    // cout << "\n";
    // for(i=0;i<=n;i++) cout << dp2[i].val() << " ";
    // cout << endl;
}