"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]
    })
    for (var x = 0; x < 1000; x++) {
        var max_i = 0
        var max_count = 0
        var all_count = 0
        for (var i = 0; i < data.length; i++) {
            var row_i = data[i]
            for (var j = 0; j < data.length; j++) {
                if (i === j) continue
                var row_j = data[j]
                if (i > j && row_i[0] < row_j[1]) {
                    data[i][2] += 1
                }
                if (j > i && row_j[0] < row_i[1]) {
                    data[i][2] += 1
                }
            }
            if (data[i][2] > max_count) {
                max_i = i
                max_count = data[i][2]
            }
            all_count += data[i][2]
        }
        // console.log(JSON.stringify(data))
        if (max_count > 0) {
            data.splice(max_i, 1)
            if (all_count / 2 === max_count) {
                console.log(data.length)
                return
            }
        } else {
            console.log(data.length)
            break
        }
    }
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));