#include <bits/stdc++.h>
using namespace std;
using pii = array<int,2>;
const int INF = 2e9+5;
int n, p, q;
int a[2005];
int f_fast(int w) {
// dp and ndp
static int dp[2005], ndp[2005];
for (int j = 0; j <= q; ++j) ndp[j] = p + 10;
// monotonic queues implemented as vector + head index
static vector<pii> sm[2005], big[2005];
static int head_sm[2005], head_big[2005];
for (int j = 0; j <= q; ++j) {
sm[j].clear(); sm[j].reserve(32); head_sm[j]=0;
big[j].clear(); big[j].reserve(32); head_big[j]=0;
}
for (int i = 1; i <= n; ++i) {
// swap dp and ndp -> copy ndp into dp
for (int j = 0; j <= q; ++j) {
dp[j] = ndp[j];
ndp[j] = p + 10; // reset for next iteration
}
for (int j = 0; j <= q; ++j) {
// pop front while out of w-window
while (head_sm[j] < (int)sm[j].size() && a[i] - a[ sm[j][head_sm[j]][1] ] + 1 > w)
++head_sm[j];
while (head_big[j] < (int)big[j].size() && a[i] - a[ big[j][head_big[j]][1] ] + 1 > 2*w)
++head_big[j];
// pop_back while last.x < dp[j]
while (!sm[j].empty() && head_sm[j] < (int)sm[j].size() && sm[j].back()[0] < dp[j])
sm[j].pop_back();
while (!big[j].empty() && head_big[j] < (int)big[j].size() && big[j].back()[0] < dp[j])
big[j].pop_back();
// push current (dp[j], i)
sm[j].push_back({dp[j], i});
big[j].push_back({dp[j], i});
// take candidates
if (head_sm[j] < (int)sm[j].size())
ndp[j] = min(ndp[j], sm[j][head_sm[j]][0] + 1);
if (j > 0 && head_big[j-1] < (int)big[j-1].size())
ndp[j] = min(ndp[j], big[j-1][head_big[j-1]][0]);
}
}
int ans = INF;
for (int j = 0; j <= q; ++j) ans = min(ans, ndp[j]);
return ans;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> p >> q;
for (int i = 1; i <= n; ++i) cin >> a[i];
if (p + q >= n) { cout << 1 << '\n'; return 0; }
sort(a+1, a+n+1);
int l = 1, r = a[n] - a[1] + 1, ans = r;
while (l <= r) {
int m = (l + r) >> 1;
if (f_fast(m) <= p) { ans = m; r = m - 1; }
else l = m + 1;
}
cout << ans << '\n';
return 0;
}
