#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;
int n,p,q,a[2005];
int nxt[2005], nxt2[2005];
int dp[2005][2005];
int f(int y, int z){
if(y == p && z == q) return 0;
if(~dp[y][z]) return dp[y][z];
int ret = 0;
if(y != p) ret = max(ret,nxt[f(y+1,z)]);
if(z != q) ret = max(ret,nxt2[f(y,z+1)]);
return dp[y][z] = ret;
}
bool trial(int x){
for (int i=0; i<n; i++) {
nxt[i] = (int)(lower_bound(a,a+n,a[i]+x) - a);
nxt2[i] = (int)(lower_bound(a,a+n,a[i]+2*x) - a);
}
nxt[n] = nxt2[n] = n;
memset(dp,-1,sizeof(dp));
return f(0,0) >= n;
}
int main(){
scanf("%d %d %d",&n,&p,&q);
for (int i=0; i<n; i++) {
scanf("%d",&a[i]);
}
p = min(p,n);
q = min(q,n);
sort(a,a+n);
int s = 0, e = 5e8;
while (s != e) {
int m = (s+e)/2;
if(trial(m)) e = m;
else s = m+1;
}
printf("%d",s);
}
