#include <bits/stdc++.h>

int main() {
	int n, q, len = 0;
	std::cin >> n >> q;
	std::vector<int> a(n);
	for (int i = 0; i < n; i++) {
	    std::cin >> a[i];
		len += a[i];
	}
	std::vector<int64_t> c(len + 1);
	int idx = 1;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < a[i]; j++) {
			c[idx] = j + 1;
			idx++;
		}
	}
	for (int i = 0; i < len; i++) {
		c[i + 1] += c[i];
	}
	for (int i = 0; i < q; i++) {
		int s;
		std::cin >> s;
		auto it = lower_bound(c.begin(), c.end(), s);
		if (it == c.end()) {
			std::cout << -1 << '\n';
		} else {
			std::cout << it - c.begin() << '\n';
		}
	}
}