#include <bits/stdc++.h>
using namespace std;
#define mp make_pair
#define pb push_back
#define fi first
#define se second
int n, p, q, x, dp[2007][2007], jump[2][2007];
vector <int> val;
bool check(int x){
for(int i = 0; i <= n + 1; i++){
for(int j = 0; j <= p; j++){
dp[i][j] = -1e9;
}
}
dp[1][0] = q;
for(int i = 1; i <= n; i++){
int pos = upper_bound(val.begin(), val.end(), val[i - 1] + x - 1) - val.begin();
jump[0][i] = pos - (i - 1);
pos = upper_bound(val.begin(), val.end(), min((long long)2e9, val[i - 1] + 2LL * x - 1)) - val.begin();
jump[1][i] = pos - (i - 1);
}
for(int i = 1; i <= n; i++){
for(int j = 0; j <= p; j++){
dp[i + jump[1][i]][j] = max(dp[i + jump[1][i]][j], dp[i][j] - 1);
if(j < p){
dp[i + jump[0][i]][j + 1] = max(dp[i + jump[0][i]][j + 1], dp[i][j]);
}
}
}
int ans = -1e9;
for(int i = 0; i <= p; i++) ans = max(ans, dp[n + 1][i]);
return (ans >= 0);
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n >> p >> q;
for(int i = 1; i <= n; i++){
cin >> x;
val.pb(x);
}
sort(val.begin(), val.end());
if(p + q >= n) return cout << 1, 0;
int l = 1, r = 1e9, mid = (l + r) >> 1;
while(l < r){
if(check(mid)) r = mid;
else l = mid + 1;
mid = (l + r) >> 1;
}
cout << l;
}
