a = input()
b = input()
x = a.split(':')
y = b.split(':')
c = int(x[0]) * 3600 + int(x[1]) * 60 + int(x[2]) -  int(y[0])*3600 - int(y[1])*60 - int(y[2])
print(c)

/**************************************************************
	Problem: 1101
	User: admin
	Language: Python
	Result: Accepted
	Time:188 ms
	Memory:34480 kb
****************************************************************/