#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pld pair<long double, int>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define ff first
#define ss second
#define SZ(x) ((int)(x).size())
#define ld long double
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int MAXN = 2e3+100;
int N, P, Q;
ll a[MAXN], nxt[2][MAXN], memo[MAXN][MAXN];
void read(){
cin >> N >> P >> Q;
for(int i = 0; i < N; i++) cin >> a[i];
}
int f(int q, int ind, ll w){
if(ind == N){
return 0;
}
if(memo[q][ind] != -1){
return memo[q][ind];
}
int ans = P+1;
int j = nxt[0][ind];
ans = min(ans, f(q, j, w) + 1);
if(q){
int j = nxt[1][ind];
ans = min(ans, f(q-1, j, w));
}
memo[q][ind] = ans;
return memo[q][ind];
}
bool good(ll w){
if(P + Q >= N) return true;
for(int i = 0; i < N; i++){
nxt[0][i] = upper_bound(a+i, a+N, a[i] + w - 1) - a;
nxt[1][i] = upper_bound(a+i, a+N, a[i] + 2*w - 1) - a;
}
memset(memo, -1, sizeof(memo));
return (f(Q, 0, w) <= P);
}
void solve(){
read();
sort(a, a+N);
ll l = 0, r = 1e10;
while(r - l > 1){
ll m = (l + r) / 2;
if(good(m)) r = m;
else l = m;
}
cout << r;
}
int main(){
ios_base::sync_with_stdio(false);
solve();
return 0;
}
