use std::io::Write;
use std::collections::*;

type Map<K, V> = BTreeMap<K, V>;
type Set<T> = BTreeSet<T>;
type Deque<T> = VecDeque<T>;

fn main() {
    input! {
        n: usize,
        p: [(i32, i32); n],
    }
    let mut p = p;
    p.sort();
    let mut dp = vec![std::i32::MAX; n + 2];
    dp[0] = 0;
    for (a, b) in p {
        let x = dp.upper_bound(&a);
        dp[x] = dp[x].min(b);
    }
    let ans = n - dp.iter().position(|p| *p == std::i32::MAX).unwrap() + 1;
    println!("{}", ans);
}

// ---------- begin input macro ----------
// reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
#[macro_export]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

#[macro_export]
macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

#[macro_export]
macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
// ---------- end input macro ----------
// ---------- begin super slice ----------
pub trait SuperSlice {
    type Item;
    fn lower_bound(&self, key: &Self::Item) -> usize
    where
        Self::Item: Ord;
    fn lower_bound_by<F>(&self, f: F) -> usize
    where
        F: FnMut(&Self::Item) -> std::cmp::Ordering;
    fn lower_bound_by_key<K, F>(&self, key: &K, f: F) -> usize
    where
        K: Ord,
        F: FnMut(&Self::Item) -> K;
    fn upper_bound(&self, key: &Self::Item) -> usize
    where
        Self::Item: Ord;
    fn upper_bound_by<F>(&self, f: F) -> usize
    where
        F: FnMut(&Self::Item) -> std::cmp::Ordering;
    fn upper_bound_by_key<K, F>(&self, key: &K, f: F) -> usize
    where
        K: Ord,
        F: FnMut(&Self::Item) -> K;
    fn next_permutation(&mut self) -> bool
    where
        Self::Item: Ord;
    fn next_permutation_by<F>(&mut self, f: F) -> bool
    where
        F: FnMut(&Self::Item, &Self::Item) -> std::cmp::Ordering;
    fn prev_permutation(&mut self) -> bool
    where
        Self::Item: Ord;
}

impl<T> SuperSlice for [T] {
    type Item = T;
    fn lower_bound(&self, key: &Self::Item) -> usize
    where
        T: Ord,
    {
        self.lower_bound_by(|p| p.cmp(key))
    }
    fn lower_bound_by<F>(&self, mut f: F) -> usize
    where
        F: FnMut(&Self::Item) -> std::cmp::Ordering,
    {
        self.binary_search_by(|p| f(p).then(std::cmp::Ordering::Greater))
            .unwrap_err()
    }
    fn lower_bound_by_key<K, F>(&self, key: &K, mut f: F) -> usize
    where
        K: Ord,
        F: FnMut(&Self::Item) -> K,
    {
        self.lower_bound_by(|p| f(p).cmp(key))
    }
    fn upper_bound(&self, key: &Self::Item) -> usize
    where
        T: Ord,
    {
        self.upper_bound_by(|p| p.cmp(key))
    }
    fn upper_bound_by<F>(&self, mut f: F) -> usize
    where
        F: FnMut(&Self::Item) -> std::cmp::Ordering,
    {
        self.binary_search_by(|p| f(p).then(std::cmp::Ordering::Less))
            .unwrap_err()
    }
    fn upper_bound_by_key<K, F>(&self, key: &K, mut f: F) -> usize
    where
        K: Ord,
        F: FnMut(&Self::Item) -> K,
    {
        self.upper_bound_by(|p| f(p).cmp(key))
    }
    fn next_permutation(&mut self) -> bool
    where
        T: Ord,
    {
        self.next_permutation_by(|a, b| a.cmp(b))
    }
    fn next_permutation_by<F>(&mut self, mut f: F) -> bool
    where
        F: FnMut(&Self::Item, &Self::Item) -> std::cmp::Ordering,
    {
        use std::cmp::Ordering::*;
        if let Some(x) = self.windows(2).rposition(|a| f(&a[0], &a[1]) == Less) {
            let y = self.iter().rposition(|b| f(&self[x], b) == Less).unwrap();
            self.swap(x, y);
            self[(x + 1)..].reverse();
            true
        } else {
            self.reverse();
            false
        }
    }
    fn prev_permutation(&mut self) -> bool
    where
        T: Ord,
    {
        self.next_permutation_by(|a, b| a.cmp(b).reverse())
    }
}
// ---------- end super slice ----------