#include <bits/stdc++.h>
    #define int long long
    using namespace std;
    signed main(){
        ios_base::sync_with_stdio(false);
        cin.tie(0);
        int n, k, q;
        cin >> n >> k >> q;
        vector<int> v(n);
        for (int i=0; i < n; i++) cin >> v[i];
        vector<pair<int, int> > srt;
        for (int i=0; i < n; i++) srt.push_back(make_pair(v[i], i));
        sort(srt.begin(), srt.end());
        int ans = 1e18;
        for (int i=0; i < n; i++){
            if (i!=0){
                if (srt[i-1].first == srt[i].first) continue;
            }
            vector<int> block;
            for (int j=0; j < i; j++) block.push_back(srt[j].second);
            block.push_back(-1);
            block.push_back(n);
            sort(block.begin(), block.end());
            vector<int> abl;
            for (int j=0; j < block.size() - 1; j++){
                vector<int> best;
                for (int p=block[j]+1; p <= block[j+1]-1; p++) best.push_back(v[p]);
                sort(best.begin(), best.end(), greater<int>());
                while (best.size() >= k){
                    abl.push_back(best.back());
                    best.pop_back();
                }
            }
            sort(abl.begin(), abl.end());
            if (abl.size() < q) continue;
            ans = min(ans, abl[q-1] - abl[0]);
        }
        cout << ans;
    }