#include<bits/stdc++.h> //:3
using namespace std;
typedef long long ll;
#define all(a) (a).begin(), (a).end()
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define pi pair<int, int>
#define sz(x) (int)((x).size())
#define int long long
const int dx[] = {0, 1, 0, -1};
const int dy[] = {1, 0, -1, 0};
const ll inf = 2e9;
const ll mod = 1e9 + 7;
const int N = 2e3 + 11;
const int X = 1e6;
const ll INF64 = 3e18 + 1;
const double eps = 1e-14;
const double PI = acos(-1);
//ifstream in(".in");
//ofstream out(".out");
int n, m, a[N], dp[N][N], S, B;
bool ok(int small, int big, int w){
memset(dp, 0x3f, sizeof(dp));
dp[0][0] = 0;
for(int j = 1; j <= small; j++) dp[0][j] = 0;
for(int i = 1; i <= n; i++){
int x = (upper_bound(a + 1, a + n + 1, a[i] + w - 1) - a) - 1;
int y = (upper_bound(a + 1, a + n + 1, a[i] + 2*w - 1) - a) - 1;
for(int j = 0; j <= small; j++){
if(j != small)dp[x][j + 1] = min(dp[x][j + 1], dp[i - 1][j]);
dp[y][j] = min(dp[y][j], dp[i - 1][j] + 1);
}
}
return (dp[n][small] <= big);
}
void solve(){
cin >> n >> S >> B;
S = min(S, n);
B = min(B, n);
for(int i = 1; i <= n; i++)cin >> a[i];
sort(a + 1, a + n + 1);
int l = 0, r = 1e9, ans = 0;
while(l <= r){
int mid = (l + r) >> 1;
if(ok(S, B, mid)){
ans = mid;
r = mid - 1;
}else l = mid + 1;
}
cout << ans << '\n';
}
int32_t main(){
ios_base :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
cout << setprecision(6) << fixed;
int T = 1;
//cin >> T;
while(T--){
solve();
}
}
