#include <bits/stdc++.h>
using namespace std;
signed main() {
ios_base::sync_with_stdio(false);
cout.tie(0); cin.tie(0);
int n, L, R; cin >> n >> L >> R;
vector<int> a(n+1);
for(int i=1; i<=n; i++) cin >> a[i];
sort(a.begin()+1, a.end());
int l=1, r=1e6, ans=1e6;
while(l <= r) {
int mid = (l + r) / 2, j = 1;
vector<int> opt(n+1), dp(n+1), good;
for(int i=1; i<=n; i++) {
while(j < i && a[i] - a[j] > mid) j++;
opt[i] = j;
}
dp[0] = 1;
good.push_back(0);
j = 0;
for(int i=L; i<=n; i++) {
while(j+1 < good.size() && good[j+1] <= i-L) j++;
if(opt[i] <= i-L+1 && good[j] >= max(i-R+1, opt[i])-1) dp[i] = 1;
if(dp[i]) good.push_back(i);
}
if(dp[n]) ans = mid, r = mid - 1;
else l = mid + 1;
}
cout << ans << '\n';
}
