import sys
input = sys.stdin.readline

mod=998244353
INV=pow(2,mod-2,mod)
POW2INV=[1]
for i in range(3*10**5):
    POW2INV.append(POW2INV[-1]*INV%mod)

N,Q=map(int,input().split())
A=list(map(int,input().split()))

INC=[0]*N
now=0

for i in range(1,N):
    if A[i-1]<A[i]:
        pass
    else:
        now=i

    INC[i]=now
    
SUM=[0]
now=1
for i in range(N):
    SUM.append(SUM[-1]+A[i]*now%mod)
    now=now*2%mod
    
for tests in range(Q):
    l,r=map(int,input().split())
    k=max(INC[r-1],l-1)+1
    
    print(((SUM[r]-SUM[k])*POW2INV[k]+A[k-1])%mod)