package main

import(
    "fmt"
    "math"
    "sort"
)

type Pair struct {
    l int
    r int
}

type PairArray []*Pair

func (p *PairArray) Len() int {
    return len(*p)
}

func (p *PairArray) Less(i, j int) bool {
    return (*p)[i].r < (*p)[j].r
}

func (p *PairArray) Swap(i, j int) {
    (*p)[i], (*p)[j] = (*p)[j], (*p)[i]
}

func main() {
    var n, l, r int
    fmt.Scanf("%d", &n)

    pairarray := make([]*Pair, 0, n)
    for i := 0; i < n; i++ {
        fmt.Scanf("%d%d", &l, &r)
        pairarray = append(pairarray, &Pair{
            l:l,
            r:r,
        })
    }

    sort.Sort((*PairArray)(&pairarray))

    res := 0
    max_R := math.MinInt32

    for i := 0; i < n; i++ {
        if pairarray[i].l > max_R {
            res++
            max_R = pairarray[i].r
        }
    }

    fmt.Printf("%d\n", res)
}