function isLeap(year) {  
    
    //Write your code here.    


if (year % 4 !== 0) {
    return "Not leap year."
}

if (year % 4 === 0 && year % 100 !== 0)  {
    return "Leap year."
}

if (year % 4 === 0 && year % 100 === 0 && year % 400 === 0) {
    return "Leap year"
}

}