use std::cmp::Ordering;
use std::cmp;
use std::cmp::min;
use std::collections::BTreeMap;
use std::process;
use std::cmp::Ord;
use std::collections::HashMap;
use std::collections::HashSet;
use std::collections::VecDeque;
use std::collections::BTreeSet;
use std::mem;
use std::collections::BinaryHeap;
use std::hash::{Hash, Hasher};

pub struct Scanner<R> {
    stdin: R,
}
 
impl<R: std::io::Read> Scanner<R> {
    pub fn read<T: std::str::FromStr>(&mut self) -> T {
        use std::io::Read;
        let buf = self
            .stdin
            .by_ref()
            .bytes()
            .map(|b| b.unwrap())
            .skip_while(|&b| b == b' ' || b == b'\n' || b == b'\r')
            .take_while(|&b| b != b' ' && b != b'\n' && b != b'\r')
            .collect::<Vec<_>>();
        std::str::from_utf8(&buf).unwrap()
            .parse()
            .ok()
            .expect("Parse error.")
    }
    pub fn vec<T: std::str::FromStr>(&mut self, n: usize) -> Vec<T> {
        (0..n).map(|_| self.read()).collect()
    }
    pub fn chars(&mut self) -> Vec<char> {
        self.read::<String>().chars().collect()
    }
}


pub trait BinarySearch<T> {
    fn lower_bound(&self, x:&T) -> usize;
    fn upper_bound(&self, x:&T) -> usize;
}

impl<T: Ord> BinarySearch<T> for VecDeque<T>{
    fn lower_bound(&self, x: &T) -> usize {
        let mut low = 0;
        let mut high = self.len();

        while low != high {
            let mid = (low + high) / 2;
            match self[mid].cmp(x) {
                Ordering::Less => {
                    low = mid + 1;
                }
                Ordering::Equal | Ordering::Greater => {
                    high = mid;
                }
            }
        }
        low
    }

    fn upper_bound(&self, x: &T) -> usize {
        let mut low = 0;
        let mut high = self.len();

        while low != high {
            let mid = (low + high) / 2;
            match self[mid].cmp(x) {
                Ordering::Less | Ordering::Equal => {
                    low = mid + 1;
                }
                Ordering::Greater => {
                    high = mid;
                }
            }
        }
        low
    }
}
impl<T: Ord> BinarySearch<T> for [T]{
    fn lower_bound(&self, x: &T) -> usize {
        let mut low = 0;
        let mut high = self.len();

        while low != high {
            let mid = (low + high) / 2;
            match self[mid].cmp(x) {
                Ordering::Less => {
                    low = mid + 1;
                }
                Ordering::Equal | Ordering::Greater => {
                    high = mid;
                }
            }
        }
        low
    }

    fn upper_bound(&self, x: &T) -> usize {
        let mut low = 0;
        let mut high = self.len();

        while low != high {
            let mid = (low + high) / 2;
            match self[mid].cmp(x) {
                Ordering::Less | Ordering::Equal => {
                    low = mid + 1;
                }
                Ordering::Greater => {
                    high = mid;
                }
            }
        }
        low
    }
}
fn comb(a:usize, b:usize,  fac:&Vec<usize>, ifac:&Vec<usize>)->usize{
        let mut a = a;
        let mut b = b;
        if a == 0 && b == 0{return 1;}
        if a<b || a<0{return 0;}
        let mut tmp = ifac[a-b]*ifac[b]%MODu;
        return tmp * fac[a]%MODu;
}
fn nHr(n:usize, r:usize, fac:&Vec<usize>, ifac:&Vec<usize>)->usize{
    if n == 0 && r == 0{
        return 1;
    }
    return comb(n+r-1, r, fac, ifac);
}
fn modinv(a:usize, M:usize)->usize{
    let mut b = M as i64;
    let mut u = 1 as i64;
    let mut v = 0 as i64;
    let mut a = a as i64;
    let mut m = M as i64;
    while(b>0){
        let mut t = a/b;
        a -= t*b;
        mem::swap(&mut a, &mut b);
        u-=t*v;
        mem::swap(&mut u, &mut v);
    }
    u%=m;
    if u<0{u+=m;}
    return u as usize;

}
fn modpow(x:usize, n:usize) -> usize{
        let mut ans = 1;
        let mut n = n as usize;
        let mut x = x;
        while(n != 0){
            if (n&1 == 1){ans = ans*x%MODu;}
            x = x*x%MODu;
            n = n>>1;
        }
        ans
}
fn modpow2(x:i64, n:i64, m:i32) -> i64{
        let mut ans = 1;
        let mut n = n as i64;
        let mut x = x;
        while(n != 0){
            if (n&1 == 1){ans = ans*x%m as i64;}
            x = x*x%m as i64;
            n = n>>1;
        }
        ans
}


fn invs(max:usize)->(Vec<usize>, Vec<usize>){
    let mut fac = vec![0;max+1];
    let mut ifac = vec![0;max+1];
    fac[0] = 1;
    ifac[0] = 1;
    for i in 0..max{

        fac[i+1] = fac[i] * (i+1)%MODu;
        ifac[i+1] = ifac[i] * modpow(i+1, MODu - 2)%MODu;
    }
    (fac, ifac)
}

#[derive(Copy, Clone, Eq, PartialEq)]
struct x{    
             a:i64,   
             b:i64, 
             c:i64,   
             d:i64,   
}            
impl Ord for x{
    fn cmp(&self, other:&Self)->Ordering{
                 (other.b * (self.a)).cmp(&((self.b)*other.a))
             }        
         }            
         impl PartialOrd for x {
             fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
                 Some(self.cmp(other))
             }        
         }          
fn gcd(a:usize, b:usize)->usize{
    if b==0{return a;}
    return gcd(b, a%b);
}
fn prime_factor(n:usize)->HashMap<usize, usize>{
    let mut res = HashMap::new();
    let mut n = n;
    for i in 2..n{
        if i*i>n{break;}
        while(n%i==0){
            *res.entry(i).or_insert(0)+=1;
            n/=i;
        }
    }
    if n != 1{
        res.insert(n, 1);
    }
    res
}
fn usize_multiply_is_overflow(a:usize, b:usize)->bool{
    if a<std::usize::MAX/b{
        return false;
    }
    else{
        return true;
    }
}

fn pow2(x:usize, n:usize) -> usize{
        let mut ans = 1;
        let mut n = n;
        let mut x = x;
        while(n != 0){
            if (n&1 == 1){
                if usize_multiply_is_overflow(ans, x){
                    return 0;
                }
                ans = ans*x;

            }
            n = n>>1;
            if n == 0{
                break;
            }
            if usize_multiply_is_overflow(x, x){
                return 0;
            }
            x = x*x;

        }
        ans
}

fn tmp(x:usize, y:usize)->usize{
    let mut ub = x+1;
    let mut lb = 1;
    while(ub-lb>1){
        let mut mid = (ub+lb)/2;
        let mut now = pow2(mid, y);
        let mut ok = true;
        if now == 0{
            ok = false;
        }
        if now>x {
            ok = false;
        }
        if ok{
            lb = mid;
        }
        else{
            ub = mid;
        }
    }
    return lb;
}

struct segment_tree<I, Op>{
    n: usize,
    dat: Vec<I>,
    op:Op,
    e:I,
}
impl<I, Op> segment_tree<I, Op>


    where Op: Fn(I, I) -> I, I:Copy{

        pub fn new(n_:usize, op: Op, e:I)->Self{
            let mut n = 1;
            while(n<n_){n*=2;}
            segment_tree{n: n, dat:vec![e; 2*n-1], op:op, e:e}
        }
        pub fn update(&mut self, k:usize, a:I){
            let mut k = k;
            k += self.n-1;
            self.dat[k] = a;
            while(k>0){
                k = (k-1)/2;
                self.dat[k] = (self.op)(self.dat[k*2 + 1], self.dat[k*2+2]);
            }
        }

        pub fn query_sub(&self, a:usize, b:usize, k:usize, l:usize, r:usize) -> I{
            if r<=a || b<=l{return self.e;}
            if a<=l && r<=b{return self.dat[k];}
            else{
                let mut vl = self.query_sub(a, b, k*2+1, l, (l+r)/2);
                let mut vr = self.query_sub(a, b, k*2+2, (l+r)/2, r);
                return (self.op)(vl, vr);
            }
        }
        pub fn query(&self, a:usize, b:usize)->I{
            return self.query_sub(a, b, 0, 0, self.n);
        }
    }
fn solve(){
    let sssss = std::io::stdin();
    let mut sc = Scanner { stdin: sssss.lock() };
    let mut N:usize = sc.read();
    let mut M:usize = sc.read();
    let mut Q:usize = sc.read();
    let mut v = vec![vec![0usize;2];Q];
    for i in 0..Q{
        for j in 0..2{
            v[i][j] = sc.read();
        }
    }
    v.sort();
    let mut z = vec![];
    let mut h = vec![];
    let mut bef = 0;
    for i in 0..Q{
        if v[i][0] != bef{
            bef = v[i][0];
            z.sort();
            z.reverse();
            h.extend(z.clone());
            z = vec![v[i][1]];
        }
        else{
            z.push(v[i][1]);   
        }
    }
    z.sort();
    z.reverse();
    h.extend(z);

    let mut dp = vec![INFu;h.len()];
    for i in 0..h.len(){
        let mut t = dp.lower_bound(&h[i]);
        dp[t] = h[i];
    }
    for i in (0..h.len()).rev(){
        if dp[i] != INFu{
            println!("{}", i+1);
            return;
        }
    }

















}


fn main(){
    solve();
}



const PI:f64 = std::f64::consts::PI;
pub static MOD:i64    = 998244353;
pub static MODu:usize = 1000000007;
pub static MODi32:i32 = 1000000007;
pub static eps:f64 = 1e-6;
const INF: i64 = 1 << 60;
const INFu:usize = 1<<62;
const INFu128:u128 = 1<<126;