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// #include <bits/stdc++.h>
#define FAST ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
#include <iostream>
#include <vector>
#include <unordered_map>
using namespace std;
int k;
vector<int64_t> sums;
unordered_map<int, unordered_map<int, int64_t>> memo;

int64_t solve(int l, int r)
{
    // printf("DBGGGG XD %d %d\n", l, r);
    if (memo[l][r])
        if (memo[l][r] == -1)
            return 0;
        else
            return memo[l][r];
    if (r - l + 1 < k)
        return 0;

    int64_t curr;
    int64_t max = 0;
    for (int i = 0; i < k && (l + i + k) <= r + 1; i++)
    {
        curr = sums[l + i + k] - sums[i + l];
        if (curr < 0)
            curr = 0;

        curr += solve(l + i + k, r);
        if (curr > max)
            max = curr;

        // printf("dbg l= %d r=%d i=%d v=%ld \n", l, r, i, curr);
    }
    if (max == 0)
        memo[l][r] = -1;
    else
        memo[l][r] = max;

    return max;
}
int main()
{
    int n, q, l, r;
    cin >> n >> k >> q;
    sums.resize(n + 1);
    sums[0] = 0;
    for (int i = 0; i < n; i++)
    {
        cin >> sums[i + 1];
        sums[i + 1] += sums[i];
    }
    for (int i = 0; i < q; i++)
    {
        cin >> l >> r;
        l--;
        r--;
        cout << solve(l, r) << endl;
    }
}