#include <bits/stdc++.h>
#define INF 1000000007
#define pb push_back
#define int long long
#define ub upper_bound
using namespace std;
int n,p,q,a[2001],S[2001],B[2001],dp[2001][2001];
bool legit(int W) {
for (int i = 0 ; i < n ; i ++) {
S[i]=ub(a,a+n,a[i]+W-1)-a;
B[i]=ub(a,a+n,a[i]+2*W-1)-a;
}
memset(dp,-1,sizeof(dp));
dp[0][0]=0;
for (int i = 0 ; i <= p ; i ++)
for (int j = 0 ; j <= q ; j ++)
if (dp[i][j]!=-1) {
if (dp[i][j]==n) return true;
dp[i+1][j]=max(dp[i+1][j],S[dp[i][j]]);
dp[i][j+1]=max(dp[i][j+1],B[dp[i][j]]);
}
return false;
}
signed main() {
cin >> n>>p>>q;
for (int i = 0 ; i < n ; i ++) cin>>a[i];
if (p+q>=n) {cout<<"1"; return 0;}
sort(a,a+n);
int L = 1 ,R = 1000000000;
while(L <= R){
if (L == R)break;
int M = L + (R-L)/2;
if(legit(M)) R = M;
else L = M + 1;
}
cout << L;
return 0;
}
