time

/*
 Author: 曹北健(37509)
 Result: AC Submission_id: 4205679
 Created at: Mon Mar 21 2022 20:32:30 GMT+0800 (China Standard Time)
 Problem: 5422  Time: 18    Memory: 1724
*/

#include<stdio.h>
int main()
{
 int a,b,c,d,e,f,g,h,t1,t2,t3,t4;
 double p;
 scanf("%d:%d %d:%d\n %d:%d %d:%d",&a,&b,&c,&d,&e,&f,&g,&h);
 t1=a*60+b;
 t2=c*60+d;
 t3=e*60+f;
 t4=g*60+h;
 if(t2<=t3)
 {
  printf("G00D!");
  }
 else if(t1>=t4)
 {
    printf("0HN0!");
 }
 else if(t1<=t3&&t3<=t2&&t2<=t4)
 {
  p=1-((1.0*(t2-t3)*(t2-t3))/((t2-t1)*(t4-t3)))/2;
  printf("%.8f",p);
 }
 else if(t3<=t1&&t1<=t2&&t2<=t4)
 {
  p=((1.0*(2*t4-t1-t2)*(t2-t1))/((t2-t1)*(t4-t3)))/2;
  printf("%.8f",p);
 }
 else if(t1<=t3&&t3<=t4&&t4<=t2)
 {
  p=((1.0*(t3+t4-2*t1)*(t4-t3))/((t2-t1)*(t4-t3)))/2;
  printf("%.8f",p);
 }
 else if(t3<=t1&&t1<=t4&&t4<=t2)
 {
  p=((1.0*(t4-t1)*(t4-t1))/((t2-t1)*(t4-t3)))/2;
  printf("%.8f",p);
 }
 return 0;
}