#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = double;
int main() {
//~ ofstream cout("out.txt");
ios::sync_with_stdio(0);
cin.tie(0);
int n;
ll d;
cin >> n >> d;
vector<ll> a(n);
vector<ll> ps(n);
for (int i = 0; i < n; ++i) {
cin >> a[i];
ps[i] += a[i];
if (i) ps[i] += ps[i - 1];
}
vector<int> left(n, -1);
for (int i = 0; i < n; ++i) {
left[i] = (a[i] == 0 ? i : -1);
if (i) left[i] = max(left[i], left[i - 1]);
}
int q;
cin >> q;
while (q--) {
int l, r;
cin >> l >> r;
--l; --r;
if (left[r] < l) {
cout << "0\n";
continue;
}
ll sum = ps[left[r]] - (l > 0 ? ps[l - 1] : 0);
if (sum > 0 && d > 1) {
cout << "-1\n";
continue;
}
cout << sum << "\n";
}
}
