import java.io.BufferedReader;
import java.io.InputStreamReader;

class Main
{
	public static void main (String[] args) throws Exception
	{
	        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
	        String[] params1 = bufferedReader.readLine().split(":");
	        int h1 = Integer.parseInt(params1[0]);
	        int m1 = Integer.parseInt(params1[1]);
	        String[] params2 = bufferedReader.readLine().split(":");
	        int h2 = Integer.parseInt(params2[0]);
	        int m2 = Integer.parseInt(params2[1]);
	        long firstTimeInMinutes = h1 * 60 + m1;
	        long secondTimeInMinutes = h2 * 60 + m2;
	        long differenceOfTimes = (1440 + (secondTimeInMinutes - firstTimeInMinutes)) % 1440;
	        secondTimeInMinutes = firstTimeInMinutes + differenceOfTimes;
	        double r = (h1 % 12 + m1 + 1);
	        long numberOfMeetings1 = firstTimeInMinutes * 11 / 720 + (long)Math.ceil((r - 1) / r);
	        long numberOfMeetings2 = secondTimeInMinutes * 11 / 720 + 1;
	        System.out.println(numberOfMeetings2-numberOfMeetings1);
	}
}