#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 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; }
};

template <class T, T Div = 2> constexpr T INFTY = std::numeric_limits<T>::max() / Div;

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

void main_() {
    usize N, M, Q;
    std::cin >> N >> M >> Q;
    Vec<Vec<usize>> adj(N);
    while (Q--) {
        usize a, b;
        std::cin >> a >> b;
        adj[a - 1].push_back(b);
    }
    Vec<usize> dp(M + 1, INFTY<usize>);
    dp[0] = 0;
    for (const auto i : rep(0, N)) {
        auto& v = adj[i];
        std::sort(v.rbegin(), v.rend());
        for (const auto j : v) {
            *std::lower_bound(dp.begin(), dp.end(), j) = j;
        }
    }
    std::cout << std::lower_bound(dp.begin(), dp.end(), INFTY<usize>) - dp.begin() - 1 << '\n';
}

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