/*
TASK:round
LANG:C
*/
#include <stdio.h>

int main()
{       int i,n,t;
        scanf("%i",&n);
        for (i = 0; i < 2*n; i++)
            scanf("%i",&t);
        if (n != 3) printf("0\n"); else printf("3\n");

        return 0;
}
