#include<bits/stdc++.h>
using namespace std;
#define task "a"
#define se second
#define fi first
#define ll long long
#define ii pair<ll, ll>
const long mxN = 3e5 + 7, nB = 550;
const ll inf = 1e18;
int n, l[mxN], r[mxN], q;
ll dif, a[mxN], ans[mxN];
vector<int> query[mxN];
bool cmp(int u, int v)
{
return r[u] < r[v];
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
// freopen(task".INP", "r", stdin);
// freopen(task".OUT", "w", stdout);
cin >> n >> dif;
for (int i = 1; i <= n; i++)
cin >> a[i];
cin >> q;
for (int i = 1; i <= q; i++)
{
cin >> l[i] >> r[i];
if (l[i] / nB == r[i] / nB)
{
ll cur = inf;
for (; r[i] >= l[i]; r[i]--)
{
ll tmp = 0;
if (a[r[i]] > cur)
tmp = (a[r[i]] - cur + dif - 1) / dif;
ans[i] += tmp;
cur = a[r[i]] - tmp * dif;
if (cur < 0)
{
ans[i] = -1;
break;
}
}
}
else
query[l[i] / nB].push_back(i);
}
for (int i = 0; i <= n / nB; i++)
{
sort(query[i].begin(), query[i].end(), cmp);
ii cur = {0, 0};
ll sum = 0, mem = 0;
int ctr = nB * (i + 1);
stack<ii> stk;
for (int id : query[i])
{
while (ctr <= r[id])
{
if (a[ctr] % dif < cur.se)
cur.fi++;
cur.se = a[ctr] % dif;
int l = ctr;
ll tmp = a[ctr] / dif - cur.fi;
while (stk.size() && stk.top().se >= tmp)
{
sum += (l - stk.top().fi) * (stk.top().se - tmp);
l = stk.top().fi;
stk.pop();
}
if (stk.empty())
mem = tmp;
stk.push({l, tmp});
ctr++;
}
ans[id] = sum;
ll cur = mem * dif + a[nB * (i + 1)] % dif;
for (int j = nB * (i + 1) - 1; j >= l[id]; j--)
{
ll tmp = 0;
if (a[j] > cur)
tmp = (a[j] - cur + dif - 1) / dif;
ans[id] += tmp;
cur = a[j] - tmp * dif;
if (cur < 0)
{
ans[id] = -1;
break;
}
}
}
}
for (int i = 1; i <= q; i++)
cout << ans[i] << '\n';
}
