import java.util.Scanner;
import java.time.YearMonth;
import java.time.Period;
 
public class Main {
    public static void main(String args[]) {
        Scanner scanner = new Scanner(System.in);
        try {
            YearMonth yearmonth0 = YearMonth.of(scanner.nextInt(), scanner.nextInt());
            YearMonth yearmonth1 = YearMonth.of(scanner.nextInt(), scanner.nextInt());
 
            if (yearmonth0.isAfter(yearmonth1)) {
                System.out.println("入力値不正");
                System.exit(0);
            }
 
            Period period = Period.between(yearmonth0.atEndOfMonth(), yearmonth1.atEndOfMonth());
            int years = period.getYears();
            int months = period.getMonths();
 
            System.out.println(years + "年" + months + "か月");
        } catch(java.time.DateTimeException e) {
            System.out.println("入力値不正");
        }
    }
}
 

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