#include<bits/stdc++.h>
using namespace std;
using intt=int32_t;
#define debug(n,m) cout<<"["<<#n<<"]->"<<n<<m
#define int long long
#define all(x) x.begin(),x.end()
#define pb push_back
const int N=10001;
const int mod=1e9;
const int inf=2e9;
int n,p,q;
int a[N];
bool check(int x){
const int m=p+q;
vector<vector<bool>> dp(n+1,vector<bool>(m+1,0));
vector<int> mem(n+1,0);
for (int i=0;i<=m;++i) {
dp[0][i]=1;
}
for (int i=1;i<=n;++i) {
for (int j=1;j<=m;++j) {
int w=x;
if (j>p) w*=2;
int dist=a[i]-a[mem[j-1]+1]+1;
if (dist<=w) {
dp[i][j]=dp[mem[j-1]][j-1];
}
if (dp[i][j]) mem[j]=i;
}
}
return dp[n][m]==1;
}
void levi() {
cin>>n>>p>>q;
a[0]=1;
for (int i=1;i<=n;++i) cin>>a[i];
sort(a+1,a+n+1);
if (p+q>=n) {
cout<<1<<'\n';
return;
}
int lo=1,hi=1e9;
int res=1e9;
while(lo<=hi) {
int mid=lo+(hi-lo)/2;
if (check(mid)) {
res=mid;
hi=mid-1;
}
else lo=mid+1;
}
cout<<res<<'\n';
}
int32_t main() {
ios_base::sync_with_stdio(0);
cin.tie(0);int tt=1;//cin>>tt;
while(tt--)levi();
}
