#include <bits/stdc++.h>
#define f0(i, n) for(int i(0); i < (n); i++)
#define f1(i, n) for(int i(1); i <= n; i++)
using namespace std;
typedef long long ll;
const int N = 2002;
int n, small, big, a[N], f[N][N], d1[N], d2[N];
bool check(int x){
f1(i, n){
d1[i] = lower_bound(a + 1, a + n + 1, a[i] - x + 1) - a;
d2[i] = lower_bound(a + 1, a + n + 1, a[i] - 2*x + 1) - a;
}
memset(f, 0x3f3f3f, sizeof(f));
f0(j, small + 1) f[0][j] = 0;
f1(i, n){
f0(j, small + 1){
/// dung 1 small
if(j > 0) f[i][j] = f[d1[i] - 1][j - 1];
f[i][j] = min(f[i][j], f[d2[i] - 1][j] + 1);
}
}
return f[n][small] <= big;
}
int main(){
ios_base::sync_with_stdio(0);
cin >> n >> small >> big;
f1(i, n) cin >> a[i];
if(small + big >= n){
cout << 1; return 0;
}
sort(a + 1, a + n + 1);
int l = 1, r = 1e9 + 1, ans = r;
while(l <= r){
int mid = (l + r)/2;
if(check(mid)) r = mid - 1, ans = mid;
else l = mid + 1;
}
cout << ans;
}
