#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define ii pair<int, int>
#define fi first
#define se second
#define pb push_back
const int N = 2009;
const int oo = 1e9;
const int mod = 1e9 + 7;
int n, P, Q;
int a[N];
bool check(int x) {
vector< vector<bool> > dp[N];
for(int i = 0; i <= n; ++i) {
dp[i].resize(P + 5);
for(int j = 0; j <= P; ++j) {
dp[i][j].assign(Q + 5, false);
}
}
// base
dp[0][P][Q] = true;
for(int i = 1; i <= n; ++i)
for(int j = 0; j <= P; ++j)
for(int t = 0; t <= Q ;++t) {
if(j < P) {
int nexpos = a[i] - x + 1;
int pos = lower_bound(a + 1, a + n + 1, nexpos) - a - 1;
dp[i][j][t] = dp[pos][j + 1][t];
}
if(t < Q && dp[i][j][t] == false) {
int nexpos = a[i] - 2*x + 1;
int pos = lower_bound(a + 1, a + n + 1, nexpos) - a - 1;
dp[i][j][t] = dp[pos][j][t + 1];
}
}
for(int j = 0; j <= P; ++j)
for(int t = 0; t <= Q ;++t)
if(dp[n][j][t])
return true;
return false;
}
signed main()
{
//freopen("test.txt", "r", stdin);
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
cin >> n >> P >> Q;
for(int i = 1; i <= n; ++i) cin >> a[i];
sort(a + 1, a + n + 1); a[0] = -oo;
if(P + Q >= n) {
cout << "1";
return 0;
}
//cout << check(3) << '\n'; return 0;
int l = 1, r = oo;
while(r > l + 1) {
int mid = (l + r)/ 2;
if(check(mid)) r = mid;
else l = mid;
}
for(int i = l; i <= r; ++i)
if(check(i)) {
cout << i; return 0;
}
}
