#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using VI = vector<int>;
using VL = vector<ll>;
using VS = vector<string>;
using VB = vector<bool>;
using VVB = vector<vector<bool>>;
using VVI = vector<VI>;
using VVL = vector<VL>;
using PII = std::pair<int, int>;
using VPII = std::vector<std::pair<int, int>>;
using PLL = std::pair<ll, ll>;
using VPLL = std::vector<std::pair<ll, ll>>;
using TI3 = std::tuple<int, int, int>;
using TI4 = std::tuple<int, int, int, int>;
using TL3 = std::tuple<ll, ll, ll>;
using TL4 = std::tuple<ll, ll, ll, ll>;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n)-1; i >= 0; i--)
#define rep2(i, s, n) for (int i = (s); i < (int)(n); i++)
#define rep3(i, s, n, d) for (int i = (s); i < (int)(n); i += (d))
#define allpt(v) (v).begin(), (v).end()
#define allpt_c(v) (v).cbegin(), (v).cend()
#define allpt_r(v) (v).rbegin(), (v).rend()
#define allpt_cr(v) (v).crbegin(), (v).crend()

const int mod1 = 1e9 + 7, mod2 = 998244353, mod3 = 1e9 + 9;
const int mod = mod1;
const ll inf = 1e18;

const string wsp = " ";
const string tb = "\t";
const string rt = "\n";

template <typename T>
void show1dvec(const vector<T> &v)
{
    if (v.size() == 0)
        return;
    int n = v.size() - 1;
    rep(i, n) cout << v[i] << wsp;
    cout << v[n] << rt;

    return;
}

template <typename T>
void show2dvec(const vector<vector<T>> &v)
{
    int n = v.size();
    rep(i, n) show1dvec(v[i]);
}

template <typename T, typename S>
void show1dpair(const vector<pair<T, S>> &v)
{
    int n = v.size();
    rep(i, n) cout << v[i].first << wsp << v[i].second << rt;
    return;
}

template <typename T, typename S>
void pairzip(const vector<pair<T, S>> &v, vector<T> &t, vector<T> &s)
{
    int n = v.size();
    rep(i, n)
    {
        t.push_back(v[i].first);
        s.push_back(v[i].second);
    }
    return;
}

template <typename T>
void maxvec(vector<T> &v)
{
    T s = v[0];
    int n = v.size();
    rep(i, n - 1)
    {
        if (s > v[i + 1])
        {
            v[i + 1] = s;
        }
        s = v[i + 1];
    }
}

template <typename T, typename S>
bool myfind(T t, S s)
{
    return find(t.cbegin(), t.cend(), s) != t.cend();
}

bool check(int y, int x, int h, int w)
{
    return 0 <= y && y < h && 0 <= x && x < w;
}

template <typename T>
vector<T> cumsum(const vector<T> &v)
{
    T s = 0;
    vector<T> ret;

    rep(i, v.size())
    {
        s += v[i];
        s %= mod;
        ret.emplace_back(s);
    }
    return ret;
}

bool iskadomatsu(int a, int b, int c)
{
    return (a != b && b != c && c != a) && ((a > b && b < c) || (a < b && b > c));
}

VS split(string s, char c)
{
    VS ret;
    string part;
    s += c;
    rep(i, s.length())
    {
        if (s[i] == c)
        {
            ret.emplace_back(part);
            part = "";
        }
        else if (s[i] != c)
        {
            part += s[i];
        }
    }
    return ret;
}

template <typename T, typename S, typename R>
ll pow_mod(T p, S q, R mod = 1ll)
{
    ll ret = 1, r = p;
    while (q)
    {
        if (q % 2)
            ret *= r, ret %= mod;
        r = (r * r) % mod, q /= 2;
    }
    return ret % mod;
}

template <typename T, typename S>
ll pow_no_mod(T p, S q)
{
    ll ret = 1, r = p;
    while (q)
    {
        if (q % 2)
            ret *= r;
        r = (r * r), q /= 2;
    }
    return ret;
}

void make_frac_tables(VL &frac_list, VL &frac_inv_list)
{
    rep(i, frac_list.size() - 1)
    {
        frac_list[i + 1] *= frac_list[i] * (i + 1);
        frac_list[i + 1] %= mod;
        frac_inv_list[i + 1] *= frac_inv_list[i] * pow_mod(i + 1, mod - 2, mod);
        frac_inv_list[i + 1] %= mod;
    }
}

ll comb(int a, int b, const VL &frac_list, const VL &frac_inv_list)
{
    if (a < b)
        return 0;
    if (b < 0)
        return 0;
    ll ret = frac_list[a];
    ret *= frac_inv_list[b];
    ret %= mod;
    ret *= frac_inv_list[a - b];
    ret %= mod;
    return ret;
}

void fall(VVI &field, int h, int w)
{
    int k;
    rep(j, w)
    {
        k = 0;
        for (int i = h; i >= 1; i--)
        {
            while (i - k > 0 && !field[i - k][j])
            {
                k++;
            }
            if (i <= k)
                break;
            swap(field[i][j], field[i - k][j]);
        }
    }
}

int getpoint(VVI &field, int h, int w, int k, int c)
{
    int l, r, score = 0;
    VPII vanish;
    rep2(i, 1, h + 1)
    {
        vanish.clear();
        l = 0, r = 1;
        rep2(j, 1, w + 1)
        {
            if (field[i][l] == field[i][j])
            {
                r++;
            }
            else
            {
                if (r - l >= k)
                    vanish.emplace_back((PII){l, r});
                l = j;
                r = l + 1;
            }
        }
        for (auto [l, r] : vanish)
        {
            score += (r - l) * field[i][l] * pow(2, c);
            rep2(j, l, r) field[i][j] = 0;
        }
    }
    return score;
}

int one_game(VVI field, int y, int x, int h, int w, int k)
{
    int totalscore = 0, one_game_score = 1, counter = 0;
    field[y + 1][x] = 0;
    while (one_game_score)
    {
        fall(field, h, w);
        one_game_score = getpoint(field, h, w, k, counter);
        totalscore += one_game_score;
        counter++;
    }
    return totalscore;
}



int main()
{

    // cin.tie(0);
    // ios::sync_with_stdio(false);

#ifdef DEBUG
    cout << "DEBUG MODE" << endl;
    ifstream in("input.txt"); //for debug
    cin.rdbuf(in.rdbuf());    //for debug
#endif

    int h, w, k, ans{0};
    cin >> h >> w >> k;
    string s;
    VVI field(h + 1, VI(w + 1, 0));
    rep(i, h)
    {
        cin >> s;
        rep(j, w)
        {
            field[i + 1][j] = s[j] - '0';
        }
    }

    rep(i, h) rep(j, w)
        ans = max(ans, one_game(field, i, j, h, w, k));
    cout << ans << rt;

    return 0;
}


Measured memory_bytes: 3984