import std.stdio, std.array, std.string, std.conv, std.algorithm;
import std.typecons, std.range, std.random, std.math, std.container;
import std.numeric, std.bigint, core.bitop;

immutable long MOD = 10^^9 + 7;

void main() {
    auto s = readln.split.map!(to!int);
    auto N = s[0];
    auto M = s[1];
    auto Q = s[2];
    auto A = iota(Q).map!(_ => readln.split.map!(x => x.to!int-1).array).array;

    A.sort!((a, b) => a[0] == b[0] ? a[1] > b[1] : a[0] < b[0]);

    auto st = new SegmentTree!(int, max, 0)(M+1);
    foreach (a; A) {
        auto x = a[0];
        auto y = a[1];
        auto v = st.query(0, y-1);
        if (v + 1 > st.query(y, y)) st.assign(y, v + 1);
    }

    st.query(0, M).writeln;
}

class SegmentTree(T, alias op, T e) {
    T[] table;
    int size;
    int offset;

    this(int n) {
        size = 1;
        while (size <= n) size <<= 1;
        size <<= 1;
        table = new T[](size);
        fill(table, e);
        offset = size / 2;
    }

    void assign(int pos, T val) {
        pos += offset;
        table[pos] = val;
        while (pos > 1) {
            pos /= 2;
            table[pos] = op(table[pos*2], table[pos*2+1]);
        }
    }

    void add(int pos, T val) {
        pos += offset;
        table[pos] += val;
        while (pos > 1) {
            pos /= 2;
            table[pos] = op(table[pos*2], table[pos*2+1]);
        }
    }

    T query(int l, int r) {
        return query(l, r, 1, 0, offset-1);
    }

    T query(int l, int r, int i, int a, int b) {
        if (b < l || r < a) {
            return e;
        } else if (l <= a && b <= r) {
            return table[i];
        } else {
            return op(query(l, r, i*2, a, (a+b)/2), query(l, r, i*2+1, (a+b)/2+1, b));
        }
    }
}