#include <bits/stdc++.h>
using namespace std;
mt19937_64 rng(time(0));
using ll = long long;
#define int long long
const int N = 2e5 + 1;
void solve() {
int n, d; cin >> n >> d;
vector<int> c(n + 1), pref (n + 1);
for (int i = 1; i <= n; ++i) {
cin >> c[i];
pref[i] = pref[i - 1] + c[i];
}
int q; cin >> q;
while (q--) {
int l, r; cin >> l >> r;
if (pref[r] - pref[l - 1] == r - l + 1) {
cout << "0\n";
continue;
}
int L = l, R = r;
while (L < R) {
int mid = (R + L) >> 1;
if (pref[r] - pref[mid - 1] == r - mid + 1) R = mid;
else L = mid + 1;
}
int ans = 0;
if (pref[r] - pref[L - 1] == r - L + 1) {
ans = pref[r] - pref[l - 1] - (pref[r] - pref[L - 1]);
} else {
ans = pref[r] - pref[l - 1];
}
if (ans) {
if (d != 1) {
cout << "-1\n";
return;
}
}
cout << ans << '\n';
}
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
#ifdef LOCAL
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif // LOCAL
int T = 1;
while (T--) solve();
return 0;
}
