n,q=map(int,input().split())
A=list(map(int,input().split()))
B=[0]*101010

p = 0;
for i in range(N):
  n = A[i]
  for j in range(n):
    B[p] = j+1
    p += 1

S = [0 for i in range(p+2)]
for i in range(p):
  S[i+1] = S[i]+B[i]
  
for i in range(q):
    s=int(input())
    ng=-1
    ok=p+1
    while abs(ok-ng)>1:
        mid=(ok+ng)//2
        if S[mid]>=s:
            ok=mid
        else:
            ng=mid
    if ok==p+1:
        print(-1)
    else:
        print(ok)
        
exit()