Substitutions [JavaScript]

function substitutions(inputData) {
    let K = Number(inputData.shift());
    let L = Number(inputData.shift());
    let M = Number(inputData.shift());
    let N = Number(inputData.shift());

    let validSubstitutions = 0;

    for (let i = K; i <= 8; i++) {
        for (let j = 9; j >= L; j--) {
            for (let k = M; k <= 8; k++) {
                for (let l = 9; l >= N; l--) {
                    if (i % 2 == 0 && j % 2 == 1 && k % 2 == 0 && l % 2 == 1) {
                        let firstNumber = "" + i + j;
                        let secondNumber = "" + k + l;

                        if (firstNumber !== secondNumber) {
                            console.log(`${firstNumber} - ${secondNumber}`);
                            validSubstitutions++;
                        } else {
                            console.log('Cannot change the same player.');
                        }

                        if (validSubstitutions == 6) {
                            break;
                        }
                    }

                    if (validSubstitutions == 6) {
                        break;
                    }
                }

                if (validSubstitutions == 6) {
                    break;
                }
            }

            if (validSubstitutions == 6) {
                break;
            }
        }
    }
}

substitutions((["7", "6", "8", "5"]));
substitutions((["6", "7", "5", "6"]));