#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double lf;
typedef pair<ll,ll> ii;
#define REP(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(ll i=1;i<=n;i++)
#define RST(i,n) memset(i,n,sizeof i)
#define SZ(a) (int)a.size()
#define ALL(a) a.begin(),a.end()
#define X first
#define Y second
#define mkp make_pair
#define pb push_back
#define eb emplace_back
#define pob pop_back
#ifdef cold66
#define debug(...) do{\
    fprintf(stderr,"%s - %d (%s) = ",__PRETTY_FUNCTION__,__LINE__,#__VA_ARGS__);\
    _do(__VA_ARGS__);\
}while(0)
template<typename T>void _do(T &&_x){cerr<<_x<<endl;}
template<typename T,typename ...S> void _do(T &&_x,S &&..._t){cerr<<_x<<", ";_do(_t...);}
template<typename _a,typename _b> ostream& operator << (ostream &_s,const pair<_a,_b> &_p){return _s<<"("<<_p.X<<","<<_p.Y<<")";}
template<typename It> ostream& _OUTC(ostream &_s,It _ita,It _itb)
{
    _s<<"{";
    for(It _it=_ita;_it!=_itb;_it++)
    {
        _s<<(_it==_ita?"":",")<<*_it;
    }
    _s<<"}";
    return _s;
}
template<typename _a> ostream &operator << (ostream &_s,vector<_a> &_c){return _OUTC(_s,ALL(_c));}
template<typename _a> ostream &operator << (ostream &_s,set<_a> &_c){return _OUTC(_s,ALL(_c));}
template<typename _a,typename _b> ostream &operator << (ostream &_s,map<_a,_b> &_c){return _OUTC(_s,ALL(_c));}
template<typename _t> void pary(_t _a,_t _b){_OUTC(cerr,_a,_b);cerr<<endl;}
#define IOS()
#else
#define debug(...)
#define pary(...)
#define endl '\n'
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0);
#endif // cold66
//}
template<class T> inline bool chkmax(T &a, const T &b) { return b > a ? a = b, true : false; }
template<class T> inline bool chkmin(T &a, const T &b) { return b < a ? a = b, true : false; }
template<class T> using MaxHeap = priority_queue<T>;
template<class T> using MinHeap = priority_queue<T, vector<T>, greater<T>>;

const ll MAXn=2e3+5,MAXlg=__lg(MAXn)+2;
const ll MOD=1000000007;
const ll INF=0x3f3f3f3f;

ll n,k,q;
ll d[MAXn],dq[MAXn];
vector<ll> dt;
bool chk(ll x){
  ll ret = 0;
  ll l=0,r=-1;
  REP (i,k-1) {
    while (r >= l && d[i] <= d[dq[r]]) r--;
    dq[++r] = i;
  }
  for (ll i=k-1;i<n;i++) {
    // debug(d[i]);
    while (r > l && dq[l] + k <= i) l++;
    while (r >= l && d[i] <= d[dq[r]]) r--;
    dq[++r] = i;
    // debug(l,r,d[dq[l]]);
    if (d[dq[l]] >= x) ret++;
  }
  debug(ret,x);
  return ret >= q;
}
int main(){
  IOS();
  cin >> n >> k >> q;
  REP (i,n) {
    cin >> d[i];
    dt.eb(d[i]);
  }
  sort(ALL(dt));

  ll ans = INF;
  REP (i,n-q+1) {
    if (chk(dt[i])) {
      ans = min(ans,dt[i+q-1]-dt[i]);
      debug(dt[i]);
    }
  }
  cout << ans << endl;
}
