#include <bits/stdc++.h>

int main() {
	long n, q, len = 0;
	scanf("%ld%ld", &n, &q);
	long a[100];
	for (long i = 0; i < n; i++) {
		scanf("%ld", &a[i]);
		len += a[i];
	}
	long c_idx[101], c[101];
	c_idx[0] = 0;
	c[0] = 0;
	for (long i = 0; i < n; i++) {
		c_idx[i + 1] = c_idx[i] + a[i];
		c[i + 1] = c[i] + a[i] * (a[i] + 1) / 2;
	}
	for (long i = 0; i < q; i++) {
		long s;
		scanf("%ld", &s);
		if (c[n] < s) {
			puts("-1");
			continue;
		}
		long l_idx = std::lower_bound(c, c + n + 1, s) - c;
		long l = c_idx[l_idx - 1];
		long d = s - c[l_idx - 1];
		printf("%ld\n", l + long(std::sqrt(2 * d) + 0.5));
	}
}