// TLE O(NQ)

#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
using ll = long long;

int main(){
	cin.tie(0)->sync_with_stdio(0);
	int n, Q;
	cin >> n >> Q;
	vector<long long> A(n + 1);
	A[0] = 1 << 30;
	for(int i = 1; i < n + 1; i++) cin >> A[i];
	int l, r;
	while(Q--){
		cin >> l >> r;
		mint ans = 0;
		for(int i = r; i >= l; i--){
			if(i == l || A[i - 1] >= A[i]){
				ans += A[i];
				break;
			}
			ans *= 2;
			ans += A[i];
		}
		cout << ans.val() << "\n";
	}
}