#include <bits/stdc++.h>
#define int long long
#define CALC(X, w) \
for (int i = 1; i <= n; i++) \
for (X[i] = X[i - 1]; \
X[i] + 1 < i && pos[i] - pos[X[i] + 1] + 1 > (w); \
X[i]++);
using namespace std;
const int MAXN = 2010;
int n, p, q;
int pos[MAXN];
int f[MAXN], g[MAXN];
int opt[MAXN][MAXN];
signed
main()
{
ios_base::sync_with_stdio(false); cin.tie(NULL);
cin >> n >> p >> q;
for (int i = 1; i <= n; i++)
cin >> pos[i];
sort(pos + 1, pos + 1 + n);
int l = 1, r = 1000000000;
while (l <= r) {
int w = (l + r) >> 1;
f[0] = g[0] = 0;
opt[0][0] = 0;
CALC(f, w);
CALC(g, 2*w);
for (int i = 1; i <= min(n, p); i++)
for (opt[i][0] = opt[i - 1][0];
opt[i][0] < n && (f[opt[i][0] + 1] <= opt[i - 1][0]);
opt[i][0]++);
for (int i = 1; i <= min(n, q); i++)
for (opt[0][i] = opt[0][i - 1];
opt[0][i] < n && (g[opt[0][i] + 1] <= opt[0][i - 1]);
opt[0][i]++);
for (int i = 1; i <= min(n, p); i++)
for (int j = 1; j <= min(n, q); j++)
for (opt[i][j] = max(opt[i][j - 1], opt[i - 1][j]);
opt[i][j] < n && (f[opt[i][j] + 1] <= opt[i - 1][j] || g[opt[i][j] + 1] <= opt[i][j - 1]);
opt[i][j]++);
if (opt[min(n, p)][min(n, q)] < n) l = w + 1;
else r = w - 1;
}
cout << l << "\n";
return 0;
}
