const N = 110;
let f = [];
for (let i = 0; i < N; i++) f[i] = new Int32Array(N).fill(1e8);

let g = [];
g.push('');

let n = 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) {
            let arr = getInputNums(line);
            arr.unshift(0);
            g.push(arr);

            if (lineIdx === n) {

                    f[0][1] = 0;
                    f[1][0] = 0;

                for (let i = 1; i <= n; i++) {
                    for (let j = 1; j <= n; j++) {
                        f[i][j] = Math.min(f[i - 1][j] , f[i][j - 1]) + g[i][j];
                    }
                }
                console.log(f[n][n]);
            }
        }
    });
});