#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#define deb(...) logger(#__VA_ARGS__, __VA_ARGS__)
template<typename ...Args>
void logger(string vars, Args&&... values) {
cerr<<vars<<" = ";
string delim="";
(...,(cerr<<delim<<values,delim=", "));
cerr<<"\n";
}
#else
#define deb(...) logger(#__VA_ARGS__, __VA_ARGS__)
template<typename ...Args>
void logger(string vars, Args&&... values) {}
#endif
#define pb push_back
#define sz(x) (int)(x.size())
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
template<typename T> inline void maxa(T& a,T b){a=max(a,b);}
template<typename T> inline void mina(T& a,T b){a=min(a,b);}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int mxN=2e3+5; //make sure this is right
const int mod=1e9+7;
int dp[mxN][mxN],a[mxN],n,p,q;
bool check(int k){
memset(dp,-1,sizeof(dp));
dp[0][0]=0;
for(int i=1;i<=n;i++){
int go=lower_bound(a,a+1+n,a[i]-k+1)-a;
int go2=lower_bound(a,a+1+n,a[i]-2*k+1)-a;
if(go) go--;
if(go2) go2--;
for(int j=1;j<=p;j++){
if(dp[go][j-1]!=-1)
dp[i][j]=dp[i][j]==-1?dp[go][j-1]:min(dp[i][j],dp[go][j-1]);
if(dp[go2][j]!=-1 && dp[go2][j]<q)
dp[i][j]=dp[i][j]==-1?dp[go2][j]+1:min(dp[i][j],dp[go2][j]+1);
}
if(dp[go2][0]!=-1 && dp[go2][0]<q)
dp[i][0]=dp[i][0]==-1?dp[go2][0]+1:min(dp[i][0],dp[go2][0]+1);
}
for(int i=0;i<=p;i++){
if(dp[n][i]!=-1)
return 1;
}
return 0;
}
int main(){
cin.sync_with_stdio(0);
cin.tie(0); cout.tie(0);
#ifdef LOCAL
freopen("input.txt","r",stdin);
freopen("output.txt","w",stdout);
#endif
cin>>n>>p>>q;
mina(p,n); mina(q,n);
for(int i=1;i<=n;i++)
cin>>a[i];
sort(a,a+1+n);
int l=1; int r=1e9;
int ans=1e9;
while(l<=r){
int mid=(l+r)>>1;
if(check(mid)){
ans=mid; r=mid-1;
} else{
l=mid+1;
}
}
cout<<ans<<"\n";
}
