Counters

Input

The first line contains an integer $N$ (0 < N \leq 1000), representing the number of ticket counters. Each of the next $N$ lines contains $4$ integers separated by spaces. The first two integers represent the opening time in hours and minutes (hours range from $0$ to $23$, and minutes range from $0$ to $59$). The last two integers represent the closing time in the same format.

The opening time indicates that the counter is operational from that minute, while the closing time indicates that the counter stops operating at that minute. For instance, if a counter is open from $10$ hours $30$ minutes to $18$ hours $30$ minutes, it operates for $480$ minutes each day. If the opening and closing times are the same, the counter operates $24$ hours a day. If the opening time is later than the closing time, the counter operates overnight, starting before midnight and ending the next day.

Output

Output a single number representing the total number of minutes per day during which all $N$ counters are simultaneously open.

Examples