package main

import . "fmt"
import . "sort"

func main() {
	var n,q int
	Scan(&n,&q)
	a := make([]int, n)
	t := make([]int, n+1)
	x := make([]int, n+1)
	for i := range a {
		Scan(&a[i])
		t[i+1] = t[i] + a[i]*(a[i]+1)/2
		x[i+1] = x[i] + a[i]
	}
	for ;q>0;q-- {
		var s int
		Scan(&s)
		p := SearchInts(t, s)
		if p == len(t) {
			Println(-1)
			continue
		}
		if s == t[p] {
			Println(x[p])
			continue
		}
		e := Search(a[p-1], func(k int) bool {
			w := t[p-1]+(k+1)*(k+2)/2
			return w > s
		})
		Println(x[p-1]+e+1)
	}
}