#include <bits/stdc++.h>
using namespace std;
#define oo 1e9
#define fi first
#define se second
#define sp(iiii) setprecision(iiii)
#define IO ios_base::sync_with_stdio(false); cin.tie(0)
#define ms(aaaa,xxxx) memset(aaaa,xxxx,sizeof(aaaa))
#define cntbit(xxxx) __builtin_popcount(xxxx)
#define getbit(xxxx,aaaa) ((xxxx>>(aaaa-1))&1)
#define _cos(xxxx) cos(xxxx*acos(-1)/180)
#define _sin(xxxx) sin(xxxx*acos(-1)/180)
#define _tan(xxxx) tan(xxxx*acos(-1)/180)
#define PE cout<<fixed
typedef long double ld;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<pair<int,int>,int> piii;
typedef pair<long long,long long> pll;
typedef pair<pair<long long,long long>,long long> plll;
const ld pi=acos(-1);
int res,n,q,p,i,a[5009],f[2009][2009];
bool ok(int x) {
for (int ii=0;ii<=p;ii++) {
for (int ij=0;ij<=q;ij++) {
f[ii][ij]=0;
}
}
for (int ii=0;ii<=p;ii++) {
for (int ij=0;ij<=q;ij++) {
if (ii>0) {
int tmp=f[ii-1][ij];
int pos=tmp+1;
for (int jj=n-pos;jj>0;jj/=2) {
while ((pos+jj<=n)&&(a[pos+jj]<=a[tmp+1]+x-1)) {
pos+=jj;
}
}
f[ii][ij]=max(f[ii][ij],pos);
}
if (ij>0) {
int tmp=f[ii][ij-1];
int pos=tmp+1;
for (int jj=n-pos;jj>0;jj/=2) {
while ((pos+jj<=n)&&(a[pos+jj]<=a[tmp+1]+2*x-1)) {
pos+=jj;
}
}
f[ii][ij]=max(f[ii][ij],pos);
}
}
}
if (f[p][q]>=n) {
return true;
}
else {
return false;
}
}
int main() {
IO;
cin>>n>>p>>q;
for (i=1;i<=n;i++) {
cin>>a[i];
}
sort(a+1,a+n+1);
if (p+q>n) {
cout<<1;
return 0;
}
else {
res=1e9;
for (int i=1e9;i>0;i/=2) {
while ((res-i>0)&&(ok(res-i))) {
res-=i;
}
}
cout<<res<<'\n';
}
}
