#include <bits/stdc++.h>
#ifdef SIR
#define err(...) fprintf(stderr, __VA_ARGS__), fflush(stderr)
#else
#define err(...) 42
#endif

using namespace std;

typedef long long ll;

const int dd = 720 * 3 + 7;
int cnt[dd];
ll dp1[dd], dp2[dd];
ll P[dd], S[dd];
int n, t, g;

struct line {
    ll k, b;
};

double inter(line a, line b) {
    return (a.b - b.b) * 1.0 / (b.k - a.k);
}

struct ConvexHull {

    vector<line> T;
    vector<double> X;
    int j = 0;

    void add(line M) {
        while (!T.empty()) {
            if (T.back().k == M.k) {
                if (T.back().b > M.b) T.pop_back(), X.pop_back();
                else return;
            } else {
                double x = inter(T.back(), M);
                if (x < X.back()) T.pop_back(), X.pop_back();
                else {
                    T.push_back(M), X.push_back(x);
                    return;
                }
            }
        }
        T.push_back(M);
        X.push_back(1e-18);
    }

    ll get(int i) {
        j = min(j, (int)X.size() - 1);
        while (j + 1 < (int)X.size() && X[j + 1] <= i) j++;
        return 1ll * T[j].k * i + T[j].b;
    }
};

ll calc(int first) {
    fill(dp1, dp1 + dd, (ll)2e18 + 1);
    fill(dp2, dp2 + dd, (ll)2e18 + 1);

    dp1[first] = first * P[first + 1] - S[first + 1];

    for (int j = 1; j < g; j++) {

        ConvexHull CH;
        for (int i = 1; i < t; i++) {
            CH.add({ -P[i], dp1[i - 1] + S[i] });
            //int cur = (int)2e9 + 1;
            /*for (int p = 1; p <= i; p++) {
                cur = min(cur, dp1[p - 1] + i * (P[i + 1] - P[p]) - (S[i + 1] - S[p]));
            }*/
            ll cur = CH.get(i) + i * P[i + 1] - S[i + 1];
            dp2[i] = min(cur, dp1[i]);
        }

        for (int i = 0; i < t; i++) {
            dp1[i] = dp2[i], dp2[i] = (int)2e9 + 1;
        }
    }

    ll ans = (ll)2e18 + 1;
    for (int i = 0; i < t; i++) {
        ans = min(ans, dp1[i] + (first + t) * (P[t] - P[i + 1]) - (S[t] - S[i + 1]));
    }
    return ans;
}

void solve() {
    cin >> n >> t >> g;
    t *= 2;

    for (int i = 0; i < n; i++) {
        int x; cin >> x;
        cnt[x % t]++;
    }

    for (int i = 0; i < t; i++) P[i + 1] = P[i] + cnt[i];
    for (int i = 0; i < t; i++) S[i + 1] = S[i] + i * cnt[i];

    ll ans = (ll)2e18 + 1;
    for (int i = 0; i < t; i++) {
        ans = min(ans, calc(i));
    }
    cout << ans << "\n";
}

int main() {
#ifdef SIR
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    solve();
    return 0;
}