#include<bits/stdc++.h>
#define int long long
using namespace std;
const int maxn = 2001;
int n, p, q, a[maxn], dp[maxn][maxn];
bool check(int mid) {
dp[0][0] = 0;
for(int i = 0; i <= p; i++) {
for(int j = 0; j <= q; j++) {
dp[i][j] = 0;
if(i > 0) {
int last = dp[i - 1][j];
int t = upper_bound(a + 1, a + n + 1, a[min(n, last + 1)] + mid - 1) - a - 1;
dp[i][j] = max(dp[i][j], t);
}
if(j > 0) {
int last = dp[i][j - 1];
int t = upper_bound(a + 1, a + n + 1, a[min(n, last + 1)] + 2 * mid - 1) - a - 1;
dp[i][j] = max(dp[i][j], t);
}
if(dp[i][j] >= n) {
return true;
}
}
}
return false;
}
signed main () {
cin >> n >> q >> p;
for(int i = 1; i <= n; i++) cin >> a[i];
sort(a + 1, a + n + 1);
if(q + p >= n) {
cout << 1;
return 0;
}
int l = 2, r = 1e9;
while(l <= r) {
int mid = (l + r) / 2;
if(check(mid)) {
r = mid - 1;
}
else l = mid + 1;
}
cout << l;
}
