#include<bits/stdc++.h>
using namespace std;
int n, p, q;
vector<int> a;
bool check(int w){
int dp[n+1][n+1]={};
int l1 = 0, l2 = 0;
for(int i = 1; i<=n; i++){
for(int j = 0; j <= n; j++) dp[i][j] = 20000;
}
for(int i = 1; i <= n; i++){
while(a[i] - w >= a[l1+1]) l1++;
while(a[i] - w-w >= a[l2+1]) l2++;
//cout << l1 <<" "<< l2 << endl;
for(int j = 0; j <= n; j++){
dp[i][j] = dp[l2][j]+1;
if(j!=0) dp[i][j] = min(dp[l1][j-1], dp[l2][j]+1);
}
//cout << endl;
}
// cout <<"\\";
// cout << dp[n][p]<<" "<< (int)(dp[n][p]<=q)<<endl;
return (dp[n][p] <=q);
}
int main(){
cin >> n >> p >> q;
a.push_back(-1);
for(int i = 0; i < n; i++) {
int x;
cin >> x;
a.push_back(x);
}
int l, r;
l = 1, r = 1000000000;
int ans = r;
p = min(n, p);
sort(a.begin(), a.end());
//for(auto i : a) cout << i << " ";
//cout << endl;
while(l<r){
int m = (l+r)/2;
//cout << m<<" "<<endl;
if(check(m)){
r = m;
ans = m;
}
else l = m+1;
//cout << endl;
}
cout << ans;
}
