#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
//using mint = modint1000000007;
using ll = long long;
using P = pair<ll, ll>;
using T = tuple<ll, ll, ll>;
template<typename T_>bool chmax(T_& a, const T_& b) { if (a < b) { a = b;return true; } else { return false; } }
template<typename T_>bool chmin(T_& a, const T_& b) { if (a > b) { a = b;return true; } else { return false; } }

#ifdef LOCAL
template<class T, class U> ostream& operator<<(ostream& o, const pair<T, U>& p) { return o << "(" << p.first << ", " << p.second << ")"; }
template<class... T> ostream& operator<<(ostream& o, const tuple<T...>& t) { o << "("; apply([&o](auto&&... a) { int c = 0; (((o << (c++ ? ", " : "") << a)), ...); }, t); return o << ")"; }
template<class V> auto operator<<(ostream& o, const V& v) -> std::enable_if_t<!std::is_same_v<V, std::string> && !std::is_same_v<V, std::string_view>, decltype(v.begin(), o)> { o << "{"; int c = 0; for (auto& x : v) o << (c++ ? ", " : "") << x; return o << "}"; }
#define dbg(...) cerr<<"["<<#__VA_ARGS__<<"]: ",([](auto&&... a){((cerr<<a<<' '),...);})(__VA_ARGS__),cerr<<'\n'
#else
#define dbg(...) void(0)
#endif

const int di[] = { -1,0,1,0 };
const int dj[] = { 0,-1,0,1 };
const int inf = 0x3f3f3f3f;
const long long INF = 0x3f3f3f3f3f3f3f3fLL;

void solve() {
    ll n, k, x; cin >> n >> k >> x;
    priority_queue<ll, vector<ll>, greater<ll>> pq;
    ll sum = 0, ans = -INF;
    for (ll i = 0; i < n; i++) {
        ll a; cin >> a;
        if (pq.size() < k) {
            pq.emplace(a);
            sum += a;
        }
        else {
            int v = pq.top();
            if (a > v) {
                pq.pop();
                pq.emplace(a);
                sum += a - v;
            }
        }
        sum -= x;
        chmax(ans, sum);
    }
    cout << ans << "\n";

}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
    }
}