"use strict"
function main(arg) {
    arg = arg.trim().split("\n")
    arg.shift()
    var data = arg
    data = data.map(e => {
        var row = e.split(" ").map(Number)
        return [row[0]-row[1], row[1]+row[0], 0]
    }).sort((a, b) => {
        return a[0] - b[0]
    })
    var error_sum = 0
    var errors = []
    for (var i = 0; i < data.length; i++) {
        var row_i = data[i]
        for (var j = i - 1; j >= 0; j--) {
            var row_j = data[j]
            if (row_j[1] > row_i[0]) {
                data[i][2] += 1
            } else {
                break
            }
        }
        for (var j = i + 1; j < data.length; j++) {
            var row_j = data[j]
            if (row_i[1] > row_j[0]) {
                // console.log(i)
                data[i][2] += 1
            } else {
                break
            }
        }
        errors.push(data[i][2])
        error_sum += data[i][2]
    }
    errors = errors.sort((a,b) => b-a)
    var p = 0
    var count = 0
    if (error_sum === 0) {
        console.log(data.length)
        return
    }
    for (var i = 0; i < errors.length; i++) {
        p += errors[i]
        count++
        if (error_sum / 2 === p) {
            console.log(data.length - count)
            return
        }
    }
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));