const N = 510;
const INF = 1e9;

let tri = [];
let f = [];
for (let i = 0; i < N; i++) {
    tri[i] = new Int32Array(N);
    f[i] = new Int32Array(N).fill(-INF);
}

let n = 0;
let cnt = 0;
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) {
            cnt++;
            let arr = getInputNums(line);
            for (let i = 1; i <= cnt; i++) {
                tri[cnt][i] = arr[i - 1];
            }
            if (lineIdx === n) {
                f[1][1] = tri[1][1];
                for (let i = 2; i <= n; i++) {
                    for (let j = 1; j <= i; j++) {
                        f[i][j] = Math.max(f[i - 1][j - 1], f[i - 1][j]) + tri[i][j];
                    }
                }
                let res = -INF;
                for (let i = 1; i <= n; i++) {
                    res = Math.max(res, f[n][i]);
                }
                console.log(res);
            }
        }
    });
});