function encryption(s: string): string {
    let stepper = Math.ceil(Math.sqrt(s.length));
    let substrings: string[] = [];
    for (let i = 0; i <= s.length; i = i + stepper) {
        substrings.push(s.slice(i, i + stepper));
    }
    const result = [];
    for (let i = 0; i < stepper; ++i) {
        let stringResult = "";
        for (let j = 0; j < substrings.length; ++j) {
            stringResult += substrings?.[j]?.[i] ?? "";
        }
        result.push(stringResult);
    }
    return result.join(" ");
}