#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
typedef long long ll;
const int INF = 1<<30;
const ll INFLL = 1LL<<60;
const ll MOD = 998244353;
const double INFD = 1.0E10;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, -1, 0, 1};
map<int, char> dm = {{0, 'D'}, {1, 'L'}, {2, 'U'}, {3, 'R'}};
// const int dx[8] = {1, 1, 0, -1, -1, -1, 0, 1};
// const int dy[8] = {0, 1, 1, 1, 0, -1, -1, -1};
using Pair = pair<ll, ll>;
using mint = atcoder::modint998244353;
// using mint = atcoder::modint1000000007;






int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(15);
    
    ll n, k, x; cin >> n >> k >> x;
    vector<ll> a(n);
    for (int i = 0; i < n; i++) cin >> a[i];
    priority_queue<ll, vector<ll>, greater<ll>> pq;
    ll ans = 0;
    ll total_ans = -INFLL;
    for (int i = 0; i < n; i++){
        pq.push(a[i]); ans += a[i];
        if (i <= k) ans -= x;
        while (pq.size() > k){
            auto y = pq.top(); pq.pop();
            ans -= y;
        }
        // cout << ans << endl;
        total_ans = max(ans, total_ans);
    }
    
    cout << total_ans << endl;
    
    return 0;
}