#[allow(unused_imports)]
use std::{
    convert::{Infallible, TryFrom, TryInto as _}, fmt::{self, Debug, Display, Formatter,},
    fs::{File}, hash::{Hash, Hasher, BuildHasherDefault}, iter::{Product, Sum}, marker::PhantomData,
    ops::{Add, AddAssign, Sub, SubAssign, Div, DivAssign, Mul, MulAssign, Neg, RangeBounds},
    str::FromStr, sync::{atomic::{self, AtomicU32, AtomicU64}, Once},
    collections::{*, btree_set::Range, btree_map::Range as BTreeRange}, mem::{swap},
    cmp::{self, Reverse, Ordering, Eq, PartialEq, PartialOrd},
    thread::LocalKey, f64::consts::PI, time::Instant, cell::RefCell,
    io::{self, stdin, Read, read_to_string, BufWriter, BufReader, stdout, Write},
};

pub trait SortD{ fn sort_d(&mut self); }
impl<T: Ord> SortD for Vec<T>{ fn sort_d(&mut self) {
    self.sort_by(|u, v| v.cmp(&u));
} }
pub trait Mx{fn max(&self, rhs: Self)->Self;}
impl Mx for f64{ fn max(&self, rhs: Self)->Self{if *self < rhs{ rhs } else { *self } }}
pub trait Mi{ fn min(&self, rhs: Self)->Self; }
impl Mi for f64{ fn min(&self, rhs: Self)->Self{ if *self > rhs{ rhs } else { *self } } }
pub fn gcd(mut a: i64, mut b: i64)->i64{ if b==0{return a;}(a,b)=(a.abs(),b.abs());while b!=0{ let c = a;a = b;b = c%b; }a }
pub fn factorial_i64(n: usize)->(Vec<i64>, Vec<i64>){ let mut res = vec![1; n+1];let mut inv = vec![1; n+1];for i in 0..n{ res[i+1] = (res[i]*(i+1)as i64)%MOD; }inv[n] = mod_inverse(res[n], MOD);for i in (0..n).rev(){ inv[i] = inv[i+1]*(i+1) as i64%MOD; }(res, inv) }
pub fn floor(a:i64, b:i64)->i64{let res=(a%b+b)%b;(a-res)/b}
pub fn extended_gcd(a:i64,b:i64)->(i64,i64,i64)
{if b==0{(a,1,0)}else{let(g,x,y)=extended_gcd(b,a%b);(g,y,x-floor(a,b)*y)}}
pub fn mod_inverse(a:i64,m:i64)->i64{let(_,x,_) =extended_gcd(a,m);(x%m+m)%m}
pub fn comb(a: i64, b: i64, f: &Vec<(i64, i64)>)->i64{
    if a<b{return 0;}else if b==0 || a==b{ return 1; }
    else{let x=f[a as usize].0;
        let y=f[(a-b) as usize].1;let z=f[b as usize].1;return((x*y)%MOD)*z%MOD;}}
pub fn factorial(x: i64)->Vec<(i64, i64)>{
    let mut f=vec![(1i64,1i64),(1, 1)];let mut z = 1i64;
    let mut inv = vec![0; x as usize+10];inv[1] = 1;
    for i in 2..x+1{z=(z*i)%MOD;
        let w=(MOD-inv[(MOD%i)as usize]*(MOD/i)%MOD)%MOD;
        inv[i as usize] = w;
        f.push((z, (f[i as usize-1].1*w)%MOD));}return f;}
pub fn fast_mod_pow(x: i64,p: usize, m: i64)->i64{
    let mut res=1;let mut t=x;let mut z=p;while z > 0{
        if z%2==1{res = (res*t)%m;}t = (t*t)%m;z /= 2; }res}
pub fn vec_out<T>(v: Vec<T>) where T: ToString{ println!("{}", v.iter().map(|x| x.to_string()).collect::<Vec<_>>().join(" ")); }
pub fn one_add_out(v: Vec<usize>){println!("{}", v.iter().map(|x| (x+1).to_string()).collect::<Vec<_>>().join(" "));}
pub trait Chmax{
    fn chmax(&mut self, rhs: Self);
}
impl Chmax for i64{
    fn chmax(&mut self, rhs: Self) {
        *self = (*self).max(rhs)
    }
}
impl Chmax for i32{
    fn chmax(&mut self, rhs: Self) {
        *self = (*self).max(rhs)
    }
}
impl Chmax for f64{
    fn chmax(&mut self, rhs: Self) {
        *self = (*self).max(rhs)
    }
}
impl Chmax for usize{
    fn chmax(&mut self, rhs: Self) {
        *self = (*self).max(rhs)
    }
}
pub trait Chmin {
    fn chmin(&mut self, rhs: Self);
}
impl Chmin for i64{
    fn chmin(&mut self, rhs: Self) {
        *self = (*self).min(rhs)
    }
}
impl Chmin for i32{
    fn chmin(&mut self, rhs: Self) {
        *self = (*self).min(rhs)
    }
}
impl Chmin for f64{
    fn chmin(&mut self, rhs: Self) {
        *self = (*self).min(rhs)
    }
}
impl Chmin for usize{
    fn chmin(&mut self, rhs: Self) {
        *self = (*self).min(rhs)
    }
}
#[allow(unused)]
mod fxhash{
    use std::hash::BuildHasherDefault;

    #[derive(Default)]
    pub struct FxHasher{
        pub hash: u64,
    }
    impl std::hash::Hasher for FxHasher{
        #[inline(always)]
        fn finish(&self) -> u64 {
            self.hash
        }

        #[inline(always)]
        fn write(&mut self, bytes: &[u8]) {
            let mut h = self.hash;
            for &b in bytes{
                h = h.rotate_left(5)^(b as u64);
                h = h.wrapping_mul(0x517cc1b727220a95);
            }
            self.hash = h;
        }
    }
    pub type FxBuildHasher = BuildHasherDefault<FxHasher>;
    pub type FxMap<K, V> = std::collections::HashMap<K, V, FxBuildHasher>;
    pub type FxSet<K> = std::collections::HashSet<K, FxBuildHasher>;
}
#[allow(unused_imports)]
//use fxhash::{FxSet, FxMap, FxBuildHasher};

#[allow(unused_imports)]
use proconio::{input, input_interactive, marker::{*}, fastout};
/* 
#[allow(unused_imports)]
use rustc_hash::FxHasher;
#[allow(dead_code)]
type FxMap<K, V> = HashMap<K, V, BuildHasherDefault<FxHasher>>;
#[allow(dead_code)]
type FxSet<K> = HashSet<K, BuildHasherDefault<FxHasher>>;
#[allow(unused_imports)]
use rand::{thread_rng, Rng, seq::SliceRandom, prelude::*};
#[allow(unused_imports)]
use itertools::{Itertools};
#[allow(unused_imports)]
use ordered_float::OrderedFloat;
#[allow(unused_imports)]
use num_bigint::BigInt;
#[allow(unused_imports)]
use ac_library::{*, ModInt998244353 as mint};
*/
#[allow(dead_code)]
//type MI = StaticModInt<Mod998244353>;pub fn factorial_mint(n: usize)->(Vec<MI>, Vec<MI>){ let mut res = vec![mint::new(1); n+1];let mut inv = vec![mint::new(1); n+1];for i in 0..n{res[i+1] = res[i]*(i+1);}inv[n] = mint::new(1)/res[n];for i in (0..n).rev(){inv[i] = inv[i+1]*(i+1);}(res, inv)}
#[allow(dead_code)]
const INF: i64 = 1<<60;
#[allow(dead_code)]
const I: i32 = 1<<28;
#[allow(dead_code)]
const MOD: i64 = 998244353;
#[allow(dead_code)]
const D: [(usize, usize); 4] = [(1, 0), (0, 1), (!0, 0), (0, !0)];
#[allow(dead_code)]
const D2: [(usize, usize); 8] = [(1, 0), (1, 1), (0, 1), (!0, 1), (!0, 0), (!0, !0), (0, !0), (1, !0)];

pub trait SegtreeMonoid{
    type S: Clone;
    fn identity()->Self::S;
    fn op(a: &Self::S, b: &Self::S)->Self::S;
}

pub struct SegmentTree2d<M> where M: SegtreeMonoid{
    h: usize,
    w: usize,
    logh: usize,
    logw: usize,
    data: HashMap<(usize, usize), M::S>,
}

impl<M> SegmentTree2d<M> where M: SegtreeMonoid{
    pub fn new(mut h: usize, mut w: usize) -> Self{
        h = h.next_power_of_two();
        w = w.next_power_of_two();
        let logh = 64-h.saturating_sub(1).leading_zeros()as usize;
        let logw = 64-w.saturating_sub(1).leading_zeros()as usize;
        let data = HashMap::default();
        SegmentTree2d{
            h, w, logh, logw, data,
        }
    }

    pub fn get(&self, u: usize, v: usize)->M::S{
        self.data.get(&(self.h+u, self.w+v)).unwrap_or(&M::identity()).clone()
    }

    fn get_sect(&self, mut l: usize, mut r: usize)->Vec<usize>{
        let mut res = Vec::new();
        while l < r{
            if l&1==1{
                res.push(l);
                l += 1;
            }
            if r&1==1{
                r -= 1;
                res.push(r);
            }
            l >>= 1;
            r >>= 1;
        }
        res
    }

    pub fn prod(&self, lx: usize, ly: usize, rx: usize, ry: usize)->M::S{
        let mut res = M::identity();
        let xs = self.get_sect(lx+self.h, rx+self.h);
        let ys = self.get_sect(ly+self.w, ry+self.w);
        for &x in &xs{
            for &y in &ys{
                res = M::op(&res, &self.data.get(&(x, y)).unwrap_or(&M::identity()));
            }
        }
        res
    }

    pub fn prod_all(&self)->M::S{
        self.data.get(&(1,1)).unwrap_or(&M::identity()).clone()
    }

    pub fn prod_x_line_all(&self, mut p: usize)->M::S{
        p += self.h;
        self.data.get(&(p, 1)).unwrap_or(&M::identity()).clone()
    }

    pub fn prod_y_line_all(&self, mut p: usize)->M::S{
        p += self.w;
        self.data.get(&(1, p)).unwrap_or(&M::identity()).clone()
    }

    pub fn prod_x_axis_all_sec(&self, mut l: usize, mut r: usize)->M::S{
        let mut res = M::identity();
        l += self.h; r += self.h;
        for x in self.get_sect(l, r){
            res = M::op(&res, &self.data.get(&(x, 1)).unwrap_or(&M::identity()));
        }
        res
    }

    pub fn prod_y_axis_all_sec(&self, mut l: usize, mut r: usize)->M::S{
        let mut res = M::identity();
        l += self.w; r += self.w;
        for y in self.get_sect(l, r){
            res = M::op(&res, &self.data.get(&(1, y)).unwrap_or(&M::identity()));
        }
        res
    }

    pub fn set(&mut self, mut u: usize, mut v: usize, x: M::S){
        u += self.h;
        v += self.w;
        self.data.insert((u, v), x);
        self.update(u, v);
    }

    pub fn push(&mut self, mut u: usize, mut v: usize, x: M::S){
        u += self.h;
        v += self.w;
        self.data.insert((u, v), M::op(&self.data.get(&(u, v)).unwrap_or(&M::identity()), &x).clone());
        self.update(u, v);
    }

    fn update(&mut self, mut u: usize, mut v: usize){
        let vv = v;
        while v > 1{
            v >>= 1;
            self.data.insert((u, v), M::op(self.data.get(&(u, 2*v)).unwrap_or(&M::identity()), self.data.get(&(u, 2*v+1)).unwrap_or(&M::identity())));
        }
        while u > 1{
            u >>= 1;
            let mut y = vv;
            loop {
                let lv = self.data.get(&(2*u, y)).unwrap_or(&M::identity()).clone();
                let rv = self.data.get(&(2*u+1, y)).unwrap_or(&M::identity()).clone();
                self.data.insert((u, y), M::op(&lv, &rv));
                if y == 1 { break; }
                let p = y >> 1;
                let lvp = self.data.get(&(u, 2*p)).unwrap_or(&M::identity()).clone();
                let rvp = self.data.get(&(u, 2*p+1)).unwrap_or(&M::identity()).clone();
                self.data.insert((u, p), M::op(&lvp, &rvp));
                y = p;
            }
        }
    }
}

struct M;
impl SegtreeMonoid for M{
    type S = i64;

    fn identity()->Self::S {
        0
    }

    fn op(&a: &Self::S, &b: &Self::S)->Self::S {
        a+b
    }
}

//#[fastout]
fn main() {
    input!{
        n: usize,
        sec: [(Usize1, Usize1); n],
    }
    let mut seg = SegmentTree2d::<M>::new(1<<20, 1<<20);
    let mut ans = 0;
    for &(u, v) in sec.iter().rev(){
        ans += seg.prod(u, u, v, v);
        seg.set(u, v, 1);
        //println!("{:?}", seg.data);
    }
    println!("{}", ans);
}