let fs = require('fs');
let input = fs.readFileSync('/dev/stdin').toString().split('\n');
let count = input[0];
let numbers = [];
for (let i = 1; i < input.length; i++) {
if (input[i] !== '') {
numbers.push(input[i].split(" ").map((str) => Number(str)));
}
}
numbers.sort((a, b) => {
if (a[1] == b[1]) return a[0] - b[0];
return a[1] - b[1];
})
var pre = 0;
var ans = 0;
for(var i=0; i<numbers.length; i++) {
if (pre <= numbers[i][0]) {
ans++;
pre = numbers[i][1];
}
}
console.log(ans)
분명 언젠가 풀어본 거 같은데 안 풀어져있네잉