#include <bits/stdc++.h>
using namespace std;
#define maxN 2001
int nextSmol[maxN], nextBeeg[maxN];
int dp[maxN][maxN];
int n, small, big;
int recur(int index, int bigCam){ //return number of small cams needed, if we want to cover all from index and onwards with only bigCam number of big cameras
if (index >= n) return 0;
if (dp[index][bigCam] != -1) return dp[index][bigCam];
return dp[index][bigCam] = min(recur(nextSmol[index], bigCam) + 1, bigCam == 0 ? INT_MAX : recur(nextBeeg[index], bigCam-1));
}
int main(){
cin >> n >> small >> big;
int arr[n];
for (int x = 0; x < n; x++) cin >> arr[x];
sort(arr, arr+n);
int l = 1, r = arr[n-1] - arr[0] + 1;
int bestAns = INT_MAX;
while (l <= r){
int w = (l+r)/2;
//time to test if valid
//we precompute the next arrays
int next = 0;
for (int x = 0; x < n; x++){
while (arr[x] - arr[next] >= w){
nextSmol[next] = x;
next++;
}
}
for (int x = next; x < n; x++){
nextSmol[x] = n; //n signifies the end
}
next = 0;
for (int x = 0; x < n; x++){
while (arr[x] - arr[next] >= 2*w){
nextBeeg[next] = x;
next++;
}
}
for (int x = next; x < n; x++){
nextBeeg[x] = n; //n signifies the end
}
/*
if (w == 4){
for (int x = 0; x < n; x++) cout << nextSmol[x] << ' ';
cout << '\n';
for (int x = 0; x < n; x++) cout << nextBeeg[x] << ' ';
cout << '\n';
}
*/
memset(dp, -1, sizeof(dp));
int ans = recur(0, min(n, big));
if (ans > small){
//illegal
//cout << "ill: " << w << ' ' << ans << '\n';
l = w+1;
}
else{
//legal
//cout << "leg: " << w << ' ' << ans << '\n';
bestAns = w;
r = w-1;
}
}
cout << bestAns;
}
