#include <bits/stdc++.h>
#define ll long long
#define ull unsigned ll
#define pb push_back
#define pa pair<int, int>
#define pall pair<ll, int>
#define fi first
#define se second
#define TASK "test"
#define Size(x) (int) x.size()
#define all(x) x.begin(), x.end()
using namespace std;
template<typename T1, typename T2> bool mini (T1 &a, T2 b) {if(a > b) a = b; else return 0; return 1;}
template<typename T1, typename T2> bool maxi (T1 &a, T2 b) {if(a < b) a = b; else return 0; return 1;}
const int MOD = 1e9 + 7;
const int LOG = 20;
const int maxn = 2e3 + 7;
const ll oo = 1e9 + 69;
int n, p, q, a[maxn], dp[maxn][maxn];
bool check(int w) {
for(int i = 1; i <= n; i++) {
int l1 = lower_bound(a + 1, a + 1 + n, a[i] - w + 1) - a;
int l2 = lower_bound(a + 1, a + 1 + n, a[i] - 2 * w + 1) - a;
for(int j = 0; j <= p; j++) {
dp[i][j] = oo;
if(j > 0) mini(dp[i][j], dp[l1 - 1][j - 1]);
mini(dp[i][j], dp[l2 - 1][j] + 1);
if(i == n && dp[i][j] <= q) return 1;
}
}
return 0;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
//freopen(TASK".inp", "r", stdin);
//freopen(TASK".out", "w", stdout);
cin>>n>>p>>q;
mini(p, n);
mini(q, n);
for(int i = 1; i <= n; i++) cin>>a[i];
sort(a + 1, a + 1 + n);
int l = 1, r = 1e9, mid, res;
while(l <= r) {
mid = l + r >> 1;
if(check(mid)) {
res = mid;
r = mid - 1;
} else l = mid + 1;
}
cout<<res;
return 0;
}
