#include <bits/stdc++.h>
#define ar array
//#define int long long
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int mod = 1e9 + 7;
const ll inf = 1e18;
const int maxn = 1e5 + 5;
struct segment_tree {
int n;
vector<pll> tree;
vector<ll> lazy;
segment_tree(int _n) : n(_n), tree(4*n), lazy(4*n) {}
void push(int u, int tl, int tr) {
if(!lazy[u]) return ;
tree[u].second += lazy[u];
tree[u].first += 1ll * (tr - tl + 1) * lazy[u];
if(tl != tr) {
lazy[2*u] += lazy[u];
lazy[2*u+1] += lazy[u];
}
lazy[u] = 0;
}
pll merge(pll a, pll b) {
return { a.first + b.first, min(a.second, b.second) };
}
void update(int u, int tl, int tr, int l, int r, ll v) {
push(u, tl, tr);
if(tl > r || l > tr) return ;
if(l <= tl && tr <= r) {
lazy[u] += v;
push(u, tl, tr);
return ;
}
int tm = (tl + tr) / 2;
update(2*u, tl, tm, l, r, v);
update(2*u+1, tm+1, tr, l, r, v);
tree[u] = merge(tree[2*u], tree[2*u+1]);
}
pll query(int u, int tl, int tr, int l, int r) {
if(tl > r || l > tr) return { 0, (ll)1e18 };
push(u, tl, tr);
if(l <= tl && tr <= r) return tree[u];
int tm = (tl + tr) / 2;
return merge(query(2*u, tl, tm, l, r), query(2*u+1, tm+1, tr, l, r));
}
void update(int l, int r, ll v) { update(1, 1, n, l, r, v); }
pll query(int l, int r) { return query(1, 1, n, l, r); }
};
signed main() {
ios_base::sync_with_stdio(false);
cout.tie(0); cin.tie(0);
ll n, A; cin >> n >> A;
vector<ll> a(n+1), pref(n+1);
for(int i=1; i<=n; i++) cin >> a[i];
for(int i=1; i<=n; i++) pref[i] = pref[i-1] + a[i];
int q; cin >> q;
vector<pii> qus[n+1];
vector<ll> ans(q+1);
for(int i=1; i<=q; i++) {
int l, r; cin >> l >> r;
qus[r].push_back({ l, i });
}
segment_tree sgt(n+1);
for(int i=1; i<=n; i++) sgt.update(i, i, a[i]);
stack<int> st;
for(int i=1; i<=n; i++) {
int p = i;
while(!st.empty()) {
ll x=sgt.query(p, p).first, y = sgt.query(p-1, p-1).first;
if(x >= y) break;
ll t = (y - x + A - 1) / A;
sgt.update(st.top(), p-1, -t * A);
p = st.top(); st.pop();
}
st.push(p);
for(auto [j, id] : qus[i]) {
auto [sum, mn] = sgt.query(j, i);
if(mn < 0) ans[id] = -1;
else ans[id] = (pref[i] - pref[j-1] - sum) / A;
}
}
for(int i=1; i<=q; i++) cout << ans[i] << '\n';
}
