#include <bits/stdc++.h>

using i32 = std::int32_t;
using u32 = std::uint32_t;
using i64 = std::int64_t;
using u64 = std::uint64_t;
using i128 = __int128_t;
using u128 = __uint128_t;
using isize = std::ptrdiff_t;
using usize = std::size_t;

class rep {
    struct Iter {
        usize itr;
        constexpr Iter(const usize pos) noexcept : itr(pos) {}
        constexpr void operator++() noexcept { ++itr; }
        constexpr bool operator!=(const Iter& other) const noexcept { return itr != other.itr; }
        constexpr usize operator*() const noexcept { return itr; }
    };
    const Iter first, last;

  public:
    explicit constexpr rep(const usize first, const usize last) noexcept : first(first), last(std::max(first, last)) {}
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

constexpr u64 ceil_log2(const u64 x) {
    u64 e = 0;
    while (((u64)1 << e) < x) ++e;
    return e;
}

template <class T> class FenwickTree {
    usize logn;
    std::vector<T> data;

  public:
    explicit FenwickTree(const usize size = 0) {
        logn = ceil_log2(size + 1) - 1;
        data = std::vector<T>(size + 1, T(0));
    }

    usize size() const { return data.size() - 1; }

    void add(usize i, const T& x) {
        assert(i < size());
        i += 1;
        while (i < data.size()) {
            data[i] += x;
            i += i & -i;
        }
    }
    void subtract(usize i, const T& x) {
        assert(i < size());
        i += 1;
        while (i < data.size()) {
            data[i] -= x;
            i += i & -i;
        }
    }

    T fold(usize l, usize r) const {
        assert(l <= r and r <= size());
        T ret(0);
        while (l < r) {
            ret += data[r];
            r -= r & -r;
        }
        while (r < l) {
            ret -= data[l];
            l -= l & -l;
        }
        return ret;
    }

    template <class F> usize max_right(const F& f) const {
        assert(f(T(0)));
        usize i = 0;
        T sum(0);
        for (usize k = (1 << logn); k > 0; k >>= 1) {
            if (i + k <= size() && f(sum + data[i + k])) {
                i += k;
                sum += data[i];
            }
        }
        return i;
    }
};

template <class T> using Vec = std::vector<T>;

void main_() {
    usize H, W, N;
    std::cin >> H >> W >> N;
    Vec<Vec<usize>> grid(H, Vec<usize>(W));
    for (auto& v : grid) {
        for (auto& x : v) {
            std::cin >> x;
            x -= 1;
        }
    }
    Vec<Vec<usize>> list(N);
    const auto add = [&](const usize x, const usize y) {
        if (x != y) {
            list[std::max(x, y)].push_back(std::min(x, y));
        }
    };
    for (const auto i : rep(0, H)) {
        for (const auto j : rep(1, W)) {
            add(grid[i][j - 1], grid[i][j]);
        }
    }
    for (const auto i : rep(1, H)) {
        for (const auto j : rep(0, W)) {
            add(grid[i - 1][j], grid[i][j]);
        }
    }
    FenwickTree<usize> fen(N - 1);
    for (const auto r : rep(0, N)) {
        for (const auto l : list[r]) {
            if (fen.fold(l, r) == 0) {
                fen.add(r - 1, 1);
            }
        }
    }
    std::cout << fen.fold(0, N - 1) + 1 << '\n';
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    main_();
    return 0;
}