#include <bits/stdc++.h>
using namespace std;
long long n, p, q;
long long a[200005];
long long dp[2005][2005];
long long smallReach[2005];
long long bigReach[2005];
#define INF 1000000
bool check(long long w){
for(long long i = 0; i <= n; ++i){
for(long long j = 0; j <= n; ++j){
dp[i][j] = INF;
}
}
for(long long i = 1; i <= n; ++i){
long long ind1 = lower_bound(a, a + n, a[i] - w + 1) - a;
long long ind2 = lower_bound(a, a + n, a[i] - 2 * w + 1) - a;
smallReach[i] = max(ind1, 1LL);
bigReach[i] = max(ind2, 1LL);
}
for(long long i = 0; i <= n; ++i){
dp[0][i] = 0;
}
for(long long i = 1; i <= n; ++i){
for(long long j = 0; j <= n; ++j){
if(j){
dp[i][j] = min(dp[bigReach[i] - 1][j] + 1, dp[smallReach[i] - 1][j - 1]);
}else{
dp[i][0] = dp[bigReach[i] - 1][0] + 1;
}
}
}
if(dp[n][p] <= q){
return true;
}
return false;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n >> p >> q;
for(long long i = 1; i <= n; ++i){
cin >> a[i];
}
sort(a + 1, a + n + 1);
p = min(p, n);
q = min(q, n);
long long l = 0;
long long r = 1000000010;
long long lc = -1;
while(l <= r){
long long mid = (l + r) / 2;
bool ch = check(mid);
if(ch){
r = mid - 1;
lc = mid;
}else{
l = mid + 1;
}
}
if(lc == -1){
while(1);
}
cout << lc << "\n";
return 0;
}
