#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < n; i++)
#define rep2(i, x, n) for (int i = x; i <= n; i++)
#define rep3(i, x, n) for (int i = x; i >= n; i--)
#define each(e, v) for (auto &e : v)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)x.size()
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const int MOD = 1000000007;
// const int MOD = 998244353;
const int inf = (1 << 30) - 1;
const ll INF = (1LL << 60) - 1;
template <typename T>
bool chmax(T &x, const T &y) {
    return (x < y) ? (x = y, true) : false;
};
template <typename T>
bool chmin(T &x, const T &y) {
    return (x > y) ? (x = y, true) : false;
};

struct io_setup {
    io_setup() {
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        cout << fixed << setprecision(15);
    }
} io_setup;

template <typename T>
void print(const vector<T> &v, T x = 0) {
    int n = v.size();
    for (int i = 0; i < n; i++) cout << v[i] + x << (i == n - 1 ? '\n' : ' ');
}

template <typename T>
void printn(const vector<T> &v, T x = 0) {
    int n = v.size();
    for (int i = 0; i < n; i++) cout << v[i] + x << '\n';
}

template <typename T>
int lb(const vector<T> &v, T x) {
    return lower_bound(begin(v), end(v), x) - begin(v);
}

template <typename T>
int ub(const vector<T> &v, T x) {
    return upper_bound(begin(v), end(v), x) - begin(v);
}

template <typename T>
void unique(vector<T> &v) {
    sort(begin(v), end(v));
    v.erase(unique(begin(v), end(v)), end(v));
}

template <typename T>
vector<int> iota(const vector<T> &v, bool greater = false) {
    int n = v.size();
    vector<int> ret(n);
    iota(begin(ret), end(ret), 0);
    sort(begin(ret), end(ret), [&](int i, int j) { return greater ? v[i] > v[j] : v[i] < v[j]; });
    return ret;
}

vector<vector<int>> es;
vector<vector<int>> S;
vector<vector<bool>> used;
vector<int> dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
int H, W, N;

void dfs(int x, int y, int k) {
    used[x][y] = true;
    rep(i, 4) {
        int nx = x + dx[i], ny = y + dy[i];
        if (nx < 0 || nx >= H || ny < 0 || ny >= W) continue;
        if (S[nx][ny] == k && !used[nx][ny])
            dfs(nx, ny, k);
        else
            es[k].eb(S[nx][ny]);
    }
}

int main() {
    cin >> H >> W >> N;

    es.resize(N);
    S.assign(H, vector<int>(W));
    used.assign(H, vector<bool>(W, false));

    rep(i, H) {
        rep(j, W) {
            cin >> S[i][j];
            S[i][j]--;
        }
    }

    rep(i, H) {
        rep(j, W) {
            if (!used[i][j]) dfs(i, j, S[i][j]);
        }
    }

    // rep(i, N) { unique(es[i]); }

    vector<int> col(N, -1);
    int p = 0;

    rep(i, N) {
        each(e, es[i]) {
            if (col[e] == p) p++;
        }
        col[i] = p;
    }

    cout << p + 1 << '\n';
}