#include <bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define debug(x) cout << "[" << #x << " = " << (x) << "]" << endl
#define prev __prev
int numPart, smallCam, largeCam;
#define MAX_N 2'020
int a[MAX_N + 2];
namespace subtask1 {
bool check() {
return (numPart <= 100);
}
bool dp[102][102][102]; // dp[i][j][k]: có thể phủ i cái đầu tiên với j (nhỏ) và k (lớn);
bool check(int g) {
FOR(i, 0, numPart) FOR(j, 0, smallCam) FOR(k, 0, largeCam) {
if (i == 0) dp[i][j][k] = true;
else dp[i][j][k] = false;
}
dp[0][0][0] = true;
FOR(i, 1, numPart) {
FOR(j, 0, smallCam)
FOR(k, 0, largeCam) {
if (j > 0) dp[i][j][k] |= dp[i][j - 1][k];
if (k > 0) dp[i][j][k] |= dp[i][j][k - 1];
// dung 1 small;
if (j > 0) FOR(prev, 1, i) if (a[i] - a[prev] + 1 <= g) dp[i][j][k] |= dp[prev - 1][j - 1][k];
// dung 1 large;
if (k > 0) FOR(prev, 1, i) if (a[i] - a[prev] + 1 <= 2 * g) dp[i][j][k] |= dp[prev - 1][j][k - 1];
}
}
return dp[numPart][smallCam][largeCam];
}
void solve() {
int l = 1, r = (int) 1e9 + 1, g, vt = -1;
while (l <= r) {
g = (l + r) >> 1;
if (check(g)) vt = g, r = g - 1;
else l = g + 1;
}
cout << vt;
}
}
int main() {
ios_base::sync_with_stdio(false);cin.tie(nullptr);
// freopen("test.inp","r",stdin);
// freopen("test.out","w",stdout);
cin >> numPart >> smallCam >> largeCam;
FOR(i, 1, numPart) cin >> a[i];
sort(a + 1, a + 1 + numPart);
if (smallCam + largeCam >= numPart) return cout << 1, 0;
if (subtask1 :: check()) return subtask1 :: solve(), 0;
return 0;
}
