const N = 5010;

let g = [];
g.push([0,0]);

let f = new Int32Array(N).fill(1);

let sort = () => {}

let buf = '';
process.stdin.on('readable', function () {
    let chunk = process.stdin.read();
    if (chunk) buf += chunk.toString();
});
let getInputNums = line => line.split(' ').filter(s => s !== '').map(x => parseInt(x));
let getInputStr = line => line.split(' ').filter(s => s !== '');
process.stdin.on('end', function () {
    buf.split('\n').forEach(function (line, lineIdx) {
        if (lineIdx === 0) {
            n = getInputNums(line)[0];
        } else if (lineIdx <= n) {
            let arr = getInputNums(line);
            arr.unshift(0);
            g.push(arr);
            if (lineIdx === n) {
                g.sort((a,b) => a[1] - b[1]);
                let res = 0;
                for (let i = 1; i <= n; i++) {
                    for (let j = 1; j < i; j++) {
                        if (g[i][1] > g[j][1] && g[i][2] > g[j][2]) f[i] = Math.max(f[i], f[j] + 1);
                    }
                    res = Math.max(res, f[i]);
                }
                console.log(g);
            }
        }
    });
});