'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.end - b.end)
	let out = []
	out.push(Xs[0])
	for(let i = 1; i < N; i++) {
		if(Xs[i] && Xs[i].start >= out[out.length - 1].end) {
			out.push(Xs[i])
		}
	}
	
	console.log(out.length)
}   

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