from bisect import bisect_right
MOD = 998244353

n, Q = map(int, input().split())
A = list(map(int, input().split()))
ind = [0]
for i in range(1, n):
    if A[i - 1] >= A[i]:
        ind.append(i)

cum = [0]
times = 1
for a in A:
    cum.append((cum[-1] + a * times) % MOD)
    times *= 2
    times %= MOD

inv2 = [1]
inv = pow(2, MOD - 2, MOD)
for _ in range(n):
    inv2.append(inv2[-1] * inv % MOD)

for _ in range(Q):
    l, r = map(int, input().split())
    l -= 1
    r -= 1
    p = bisect_right(ind, r)
    l = max(l, ind[p - 1])
    ans = A[l]
    if l != r:
        ans += (cum[r + 1] - cum[l + 1]) * inv2[l + 1] % MOD
        ans %= MOD

    print(ans)