#ifdef __AVX2__
#pragma GCC target "avx2"
#endif
#pragma GCC optimize "O3"
#pragma GCC optimize "unroll-loops"
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
#define int long long
#define elif else if
#define all(l) begin(l),end(l)
#define rall(l) rbegin(l),rend(l)
#define append push_back
#define print(l) for(auto i:l) cout<<i<<' '; cout<<endl;
#define pprint(a,b) cout<<a<<' '<<b<<endl;
#define inp(l) for(auto &i:l) cin>>i;
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define pai make_pair
#define endl "\n"
#define pii pair<int,int>
#define fi first
#define se second
#define vec vector
// const int mod=998244353;
const int mod1=998244353;
const int mod=1e9+7;
const int N=3e5+5;
int c[N];
int iter=1,itera=1;
void solve(){
int n,d;
cin>>n>>d;
for(int i=1;i<=n;i++) cin>>c[i];
vec<int>o(n+1,0),p(n+1,0);
for(int i=1;i<=n;i++){
p[i]=p[i-1]+c[i];
if(c[i]==1) o[i]=o[i-1]+1;
}
int q;
cin>>q;
for(int i=1;i<=q;i++){
int l,r;
cin>>l>>r;
if((p[r]-p[l-1])<=o[r]) cout<<"0\n";
else{
if(d==1) cout<<p[r]-p[l-1]-o[r]<<endl;
else cout<<"-1\n";
}
}
}
signed main(){
// freopen("","r",stdin);
// freopen("","w",stdout);
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
// cin>>itera;
for(iter=1;iter<=itera;iter++) solve();
}
