a,b=list(map(int,input().split(":")))
c,d=list(map(int,input().split(":")))
t=c*30+(30*d/60)-(a*30+(30*b/60))
print("%.1lf"%t)

/**************************************************************
	Problem: 1321
	User: admin
	Language: Python
	Result: Accepted
	Time:136 ms
	Memory:34480 kb
****************************************************************/