const N = 5010;

let q = [];

let f = new Int32Array(N);

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 === 1) {
            let res = 0;
            let arr = getInputNums(line);
            for (let i = 1; i <= arr.length; i++) f[i] = q[i] = arr[i - 1];
            for (let i = 1; i <= n; i++) {
                for (let j = 1; j < i; j++) {
                    if (q[i] > q[j]) {
                        f[i] = Math.max(f[i], f[j] + q[i]);
                    }
                }
                res = Math.max(res, f[i]);
            }
            console.log(res);
        }
    });
});