#include<bits/stdc++.h>
using namespace std;
const int MAXN = 2010;
int dp[MAXN][MAXN];
int v[MAXN];
int N, P, Q;
int go[MAXN][2];
bool can(int w){
int last_0 = 0;
int last_1 = 0;
for(int i = 0; i < N; ++i){
while(last_0 < N && v[last_0] - v[i] <= w - 1)
last_0++;
while(last_1 < N && v[last_1] - v[i] <= 2LL*w - 1)
last_1++;
go[i][0] = last_0;
go[i][1] = last_1;
// cout << i << " " << last_0 << " " << last_1 << "\n";
}
int maxp = min(N, P);
for(int i = 0; i <= N; ++i){
for(int j = 0; j <= maxp; ++j){
dp[i][j] = INT_MAX;
}
}
// P: w 0
// Q: 2w 1
dp[0][0] = 0;
for(int i = 0; i < N; ++i){
for(int j = 0; j <= maxp; ++j){
if(dp[i][j] == INT_MAX) continue;
dp[go[i][0]][j + 1] = min(dp[go[i][0]][j + 1], dp[i][j]);
dp[go[i][1]][j] = min(dp[go[i][1]][j], dp[i][j] + 1);
}
}
// cout << w << ":\n";
int mini = INT_MAX;
for(int j = 0; j <= maxp; ++j){
// cout << j << " : " << dp[N][j] << "\n";
mini = min(mini, dp[N][j]);
}
return mini <= Q;
}
int main(){
cin.tie(NULL)->sync_with_stdio(false);
cin >> N >> P >> Q;
for(int i = 0; i < N; ++i) cin >> v[i];
sort(v, v + N);
// can(3);
// return 0;
int pot = (1 << 30);
int ans = 0;
while(pot){
int mans = ans + pot;
if(!can(mans)) ans = mans;
pot /= 2;
}
cout << ans + 1 << "\n";
}
