let pad = [
        '123',
        '456',
        '789'
];

let code = '';
let [i, j] = [1, 1];

while let $line = read() {
        for c in line {
                let [ni, nj] = match c {
                        'U' => [i - 1, j],
                        'D' => [i + 1, j],
                        'L' => [i, j - 1],
                        'R' => [i, j + 1]
                };
                let valid = k -> (..3).contains?(k);
                if (valid(ni) && valid(nj))
                        [i, j] = [ni, nj];
        }
        code += pad[i][j];
}

print(code);