while 1:

    try:

        n , m = map(int, input().split())

        a = list(map(int,input().split()))

        total = [0]+[ sum(a[0:j+1]) for j in range(len(a)) ]

        for i in range(m):

            x , y = map(int,input().split())

            print(total[y] -  total[x-1])

    except:

        break