#include<iostream> 
#include<string>
#include<iomanip>
using namespace std;
int main() 
{
	string a, b;
	cin >> a >> b;
	double deg = ((b[0] - '0') * 600 + (b[1] - '0') * 60 + (b[3] - '0') * 10 + (b[4] - '0') - (a[0] - '0') * 600 - (a[1] - '0') * 60 - (a[3] - '0') * 10 - (a[4] - '0')) * 0.5;
	cout << fixed << setprecision(1) << deg << endl;
	return 0;
}
/**************************************************************
	Problem: 1321
	User: admin
	Language: C++
	Result: Accepted
	Time:12 ms
	Memory:2076 kb
****************************************************************/