Substitute

function substitute(input) {
    let counter = 0;
    for (let k = Number(input[0]); k < 9; k++) {
        for (let l = 9; l >= Number(input[1]); l--) {
            for (let m = Number(input[2]); m < 9; m++) {
                for (let n = 9; n >= Number(input[3]); n--) {
                    if (k % 2 === 0 && m % 2 === 0 && l % 2 === 1 && n % 2 === 1) {
                        if (k === m && l === n) {
                            console.log("Cannot change the same player.");
                        } else {
                            console.log(`${k}${l} - ${m}${n}`);
                            if (++counter === 6) {
                                return;
                            }
                        }
                    }
                }
            }
        }
    }
    return;
}