#include <bits/stdc++.h>
#define pb push_back
#define pf push_front
using namespace std;
#define F first
#define S second
typedef long long ll;
#define pii pair <int, int>
#define pll pair <ll, ll>
typedef long double ld;
const ll N = 2000 + 100, M = 4096 + 10, len = 21, inf = 1e18;
const ll mod = 1e9 + 7;
ll um(ll a, ll b){
return (1LL * a * b) % mod;
}
ll subr(ll a, ll b){
return ((1LL * a - b) % mod + mod) % mod;
}
int pos[N], n, a, b, cur[N][N];
bool calc(int x){
cur[0][a] = b;
//cout << x << endl;
for(int i = 0; i < n; i++){
int lx = n, lxx = n;
for(int j = i; j < n; j++){
if(pos[j] > pos[i] + x - 1) lx = min(j, lx);
if(pos[j] > pos[i] + 2 * x - 1){
lxx = j;
break;
}
}
//cout << i << " "<< lx << " " << lxx << endl;
for(int j = 0; j <= a; j++){
if(cur[i][j] > 1) cur[lxx][j] = max(cur[lxx][j], cur[i][j] - 1);
if(j > 0) cur[lx][j - 1] = max(cur[lx][j - 1], cur[i][j]);
}
for(int j = 0; j <= a; j++){
cur[i][j] = 0;
}
}
bool can = false;
for(int i = 0; i <= a; i++){
if(cur[n][i] >= 1) can = true;
cur[n][i] = 0;
}
return can;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> a >> b;
b++;
if(a + b - 1 >= n){
cout << 1;
return 0;
}
for(int i = 0; i < n; i++){
cin >> pos[i];
}
sort(pos, pos + n);
int l = 0, r = 1e9;
while(r - l > 1){
int mid = (r + l) / 2;
if(calc(mid)) r = mid;
else l = mid;
}
cout << r;
return 0;
}
