#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;
vector<int> mxl (n + 1);
for (int i = 1; i <= n; ++i) {
if (c[i]) mxl[i] = mxl[i - 1] + 1;
}
while (q--) {
int l, r; cin >> l >> r;
int ans = 0, wr = r;
while (r >= l) {
if (!c[r]) break;
r --;
}
if (min (mxl[wr], wr - l + 1) != wr - r) assert(0);
if (r >= l) 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;
}
