#include <bits/stdc++.h>
using namespace std;
void setup()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
struct SEGMENT_TREE
{
long long tree[1200000], rem[1200000];
inline void Init()
{
fill_n(tree, 1200000, 0);
fill_n(rem, 1200000, -1);
}
inline void UpdateNode(int ind, int l, int r)
{
if (rem[ind] != -1)
{
tree[ind] = rem[ind] * (r - l + 1);
if (l < r)
{
rem[ind << 1] = rem[ind << 1 | 1] = rem[ind];
}
rem[ind] = -1;
}
}
inline void Update(int ind, int l, int r, int x, int y, long long v)
{
UpdateNode(ind, l, r);
if (r < x || y < l)
{
return;
}
if (x <= l && r <= y)
{
rem[ind] = v;
UpdateNode(ind, l, r);
return;
}
int m = (l + r) >> 1;
Update(ind << 1, l, m, x, y, v);
Update(ind << 1 | 1, m + 1, r, x, y, v);
tree[ind] = tree[ind << 1] + tree[ind << 1 | 1];
}
inline long long Get(int ind, int l, int r, int x, int y)
{
UpdateNode(ind, l, r);
if (r < x || y < l)
{
return 0;
}
if (x <= l && r <= y)
{
return tree[ind];
}
int m = (l + r) >> 1;
return Get(ind << 1, l, m, x, y) + Get(ind << 1 | 1, m + 1, r, x, y);
}
} st;
int n, q, x, y;
long long d;
long long a[300000], b[300000], pre[300000], res[300000];
vector<pair<int, int>> query[300000];
vector<array<long long, 3>> v;
array<long long, 3> cur;
int main()
{
setup();
cin >> n >> d;
for (int i = 0; i < n; ++i)
{
cin >> a[i];
}
for (int i = n - 2; i >= 0; --i)
{
b[i] = max(0LL, a[i] - (a[i + 1] - d * b[i + 1]) + d - 1) / d;
}
for (int i = 1; i < n; ++i)
{
pre[i] = b[i] + pre[i - 1];
}
cin >> q;
for (int i = 0; i < q; ++i)
{
cin >> x >> y;
query[y - 1].push_back({x - 1, i});
}
for (int i = 0; i < n; ++i)
{
cur = {i, i, b[i]};
while (!v.empty() && v.back()[2] >= cur[2])
{
cur[0] = v.back()[0];
v.pop_back();
}
v.push_back(cur);
st.Update(1, 0, n - 1, cur[0], cur[1], cur[2]);
for (auto &j : query[i])
{
res[j.second] = pre[i] - pre[j.first] + b[j.first];
if ((b[j.first] - st.Get(1, 0, n - 1, j.first, j.first)) * d > a[j.first])
{
res[j.second] = -1;
}
else
{
res[j.second] -= st.Get(1, 0, n - 1, j.first, i);
}
}
}
for (int i = 0; i < q; ++i)
{
cout << res[i] << "\n";
}
return 0;
}
