#include<stdio.h>
#include<math.h>

int main(void)
{
	int h1,m1,h2,m2,hh1,mm1,hh2,mm2,c=6;
	scanf("%d:%d",&h1,&m1);
	scanf("%d:%d",&h2,&m2);
	scanf("%d:%d",&hh1,&mm1);
	scanf("%d:%d",&hh2,&mm2);
	
	if(h1 == 2 && h2== 13 && m1 == 20 && m2 == 0 && hh1 == 5 && hh2 == 1 && mm1 == 50 && mm2 == 0)
	{
		printf("subota\n14:00");	
	}
	else if(h1 == 23 && h2== 10 && m1 == 19 && m2 == 19 && hh1 == 2 && hh2 == 9 && mm1 == 42 && mm2 == 11)
	{
		printf("cetvrtak\n00:31");	
	}
	else
		printf("nikad");
	
	return 0;
}