'use strict'
const main = arg => {
	const input = arg.trim().split("\n");
	let N = Number(input[0])
	let Xs = input.slice(1, input.length).map((x) => {
		return { 
			start : Number(x.split(' ')[0]) - Number(x.split(' ')[1]), 
			end: Number(x.split(' ')[0]) + Number(x.split(' ')[1])
		}
	})
	Xs.sort((a, b) => a.start - b.start)
	for(let i = 1 ; i < Xs.length ; i++) {
		// 前のロボットとかぶっている
		if(Xs[i - 1].end > Xs[i].start) {
			Xs.splice(i, 1)
			i--
		}
	}
	console.log(Xs.length)
}   

main(require('fs').readFileSync('/dev/stdin', 'utf8'));