// #include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <unordered_map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
using namespace std;
#define int long long
#define endl "\n"
#define fi first
#define se second
const int M=998244353;
const int inf = 1e14;
const int LOG=20;
const int N=3e5+5;
int n , m , c , w , k , t=1 , q=1 , x , y , z , l , r;
void solve()
{
cin >> n >> x;
vector<int>a(n+1);
for (int i=1;i<=n;i++){
cin >> a[i];
}
cin >> q;
for (int o=0;o<q;o++){
cin >> l >> r;
c=0;
vector<int>b=a;
bool f=0;
for (int i=l;i<=r;i++){
a[i]-=c;
int u=a[i]-(a[i]/x)*x;
if (u<0)f=1;
c+=u;
a[i]-=u;
}
for (int i=l;i<=r;i++){
if (a[i]<0 or a[i]%x){
f=1;
}
}
if (f){
cout << -1 << endl;
a=b;
continue;
}
int mn=inf;
c=0;
for (int i=r;i>=l;i--){
int u=min(mn,a[i]);
a[i]-=u;
int y=((a[i]+x-1)/x)*x-a[i];
u+=y;
a[i]+=y;
mn=min(mn,u);
c+=a[i]/x;
}
cout << c << endl;
a=b;
}
}
signed main()
{
ios::sync_with_stdio(0);//DO NOT USE IN INTERACTIVE
cin.tie(0), cout.tie(0);//DO NOT USE IN INTERACTIVE
cout << fixed << setprecision(9);
// int t=1;
// cin >> t;
for (int _=1;_<=t;_++){
solve();
q++;
}
}
