N,Q = map(int,input().split())
A = list(map(int,input().split()))
B = [0 for i in range(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()