#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> pi;
typedef pair<double, double> pd;
typedef vector<ll> vi;
typedef vector<vector<ll>> vvi;
typedef vector<vector<pi>> vvpi;
typedef vector<pi> vpi;

ll INF = 2e18;
double eps = 1e-12;

#define forn(i, e) for (ll i = 0; i < e; i++)
#define forsn(i, s, e) for (ll i = s; i < e; i++)
#define rforn(i, s) for (ll i = s; i >= 0; i--)
#define rforsn(i, s, e) for (ll i = s; i >= e; i--)
#define ln "\n"
#define dbg(x) cout << #x << " = " << x << ln
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define sz(x) ((ll)(x).size())

void fast_cin()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}

void read(vi &x)
{
    for (ll i = 0; i < sz(x); i++)
    {
        cin >> x[i];
    }
    return;
}

void read(vvi &x)
{
    for (ll i = 0; i < sz(x); i++)
    {
        for (ll j = 0; j < sz(x[i]); j++)
        {
            cin >> x[i][j];
        }
    }
    return;
}

void solve()
{
    ll n, q, k;
    cin >> n >> q >> k;
    vi a(n);
    read(a);
    vi pre(n), post(n), mid(n);
    forn(i, n)
    {
        if (i == 0)
        {
            pre[i] = k - 1;
            post[i] = a[i + 1] - 2;
            continue;
        }
        else if (i == n - 1)
        {
            pre[i] = k - a[i - 1] - 1;
            post[i] = k - 1;
            continue;
        }
        pre[i] = k - a[i - 1] - 1;
        post[i] = a[i + 1] - 2;
        mid[i] = a[i + 1] - a[i - 1] - 2;
    }
    for (ll i = 2; i < n - 1; i++)
    {
        mid[i] += mid[i - 1];
    }
    // forn(i,n)
    // {
    //     dbg(pre[i]);
    //     dbg(post[i]);
    //     dbg(mid[i]);
    // }
    ll l, r;
    while (q--)
    {

        cin >> l >> r;

        if (l == r)
        {
            cout << k - 1 << ln;
            continue;
        }

        ll tmp = (l + 1 < r) ? (mid[r - 2] - mid[l - 1]) : 0;
        ll ans = post[l - 1] + pre[r - 1] + tmp;
        cout << ans << ln;
    }
    return;
}

int main()
{
    // #ifndef ONLINE_JUDGE
    //     freopen("input.txt", "r", stdin);
    //     freopen("output.txt", "w", stdout);
    // #endif
    fast_cin();
    ll t = 1;
    // cin >> t;
    for (int it = 1; it <= t; it++)
    {
        // cout << "Case #" << it + 1 << ": ";
        solve();
    }
    return 0;
}