java 版

public class hello{
    public static int f (int a, int b){
        if (b == 0)return a;
        return f (b, a%b);
    }
    public static void Main (String [] args){
        Scanner input = new Scanner(System.in);
        int n = scanner.nextInt();
        int m = scanner.nextInt();
        int l = f(n,m);
        System.out.println(l);
}