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)