Bad return type in lambda expression void converted to int

Question

I've just started out using lambdas and wrote this code to calculate if an input year is a leapyear or not, using lambdas.

I get the error "bad return type in lambda expressions void cannot be converted to int" and to no avail searched for answers.

import java.util.Scanner;

interface LeapYears {
    int leapYear(int years);
}

public class LeapYear {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        LeapYears leap = (t) -> {
            System.out.print("Year between 2012 and 2060: ");
            int years = in.nextInt();
            boolean x = years % 4 == 0,
                    y = years % 100 != 0,
                    z = years % 400 == 0;

            boolean isLeapYear = (x && y) || z;
            if (isLeapYear == true) {
                return System.out.println(years + " Is a Leapyear");
            } else {
                return System.out.println(years + " is not a Leapyear");
            }
        }
    }
}