#include <bits/stdc++.h>
using namespace std;
#ifndef ONLINE_JUDGE
    #include "debug.h"
#endif
#define int long long 
const int mod = 1e9 + 7, mxn = 2e5 + 1, inf = LLONG_MAX;

int solve(){
    int n, k, q;
    cin>> n>> q>> k;
    vector<int> a(n);
    for(int i = 0; i < n; i++){
        cin>> a[i];
    }
    vector<int> cnt(n, 0);
    for(int i = 1; i < n - 1; i++){
        cnt[i] = (a[i] - a[i - 1] - 1) + (a[i + 1] - a[i] - 1);
    }
    for(int i = 1; i < n; i++){
        cnt[i] += cnt[i - 1];
    }
    while(q--){
        int l, r;
        cin>> l>> r;
        if(l == r){
            cout<< (k - 1)<< "\n";
            continue;
        }
        l--, r--;
        int ans = a[l] - 1 + a[l + 1] - a[l] - 1 + k - a[r] + a[r] - a[r - 1] - 1 + cnt[r - 1] - cnt[l];
        cout<< ans<< "\n"; 
    }
    return 0;
}

signed main(){
    ios_base::sync_with_stdio(NULL);cin.tie(NULL);cout.tie(NULL);
    int t = 1;
    // cin>> t;
    while(t--){
        solve();
    }
}