#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define all(v) begin(v), end(v)
#define pi pair<int, int>
#define vi vector<int>
using namespace std;
const int N = 2e3+3;
int n, p, q, a[N];
int dp[N][N];
bool ck(int d){
memset(dp, 0, sizeof(dp));
dp[1][0] = lower_bound(a+1, a+n+1, a[1] + d) - a - 1;
dp[0][1] = lower_bound(a+1, a+n+1, a[1] + 2*d) - a - 1;
// cout << d << "\n";
for(int i = 1; i <= p; i++){
for(int j = 1; j <= q; j++){
int ff = lower_bound(a+1, a+n+1, a[dp[i-1][j] + 1] + d) - a - 1;
dp[i][j] = max(dp[i][j], ff);
ff = lower_bound(a+1, a+n+1, a[dp[i][j-1] + 1] + 2*d) - a - 1;
dp[i][j] = max(dp[i][j], ff);
// cout << dp[i][j] << " ";
}
// cout << '\n';
}
return dp[p][q] == n;
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n >> p >> q;
if(p + q >= n){
cout << 1;
return 0;
}
p = min(p, n), q = min(q, n);
for(int i = 1; i <= n; i++) cin >> a[i];
a[n+1] = a[n];
sort(a+1, a+n+1);
int ans, L = 1, R = 1e9, mid;
while(L <= R){
mid = (L+R)/2;
if(ck(mid)){
ans = mid;
R = mid - 1;
}
else L = mid + 1;
}
cout << ans;
return 0;
}
