#include<iostream>
#include <math.h>
#include <iomanip>
using namespace std;


int main()
{
    int h,m;  //h is hour, m is minutes
	char colon;
	double anglePerHour = 360/12; //30
	double anglePerMinute = 360/60; //6

	while(cin>>h>>colon>>m && !(h==0 && m==0)){
		double hAngle = (double)h*anglePerHour + (double)m/60 *anglePerHour;
		double mAngle = m*anglePerMinute;
		double angle = fabs( hAngle-mAngle);
		if(angle>180){
			angle = 360 -angle;
		}
		cout << fixed << setprecision(3)<<angle<<endl;  //注意還有cout.
	}

    return 0;
}