Film Festival

The festival of French cinema, which will be held over one day, will demonstrate $n$ films, for each of them we know the start time and and duration time of the show. Viewing takes place in a theater having sufficient number of halls for demonstrations, the transition between the halls takes less than a minute, that is, as soon as next minute after the previous session, you can catch the other. What is the largest number of films can be watched completely?

Input

First line contains the number of films $n(1\le n\le 100)$. Next $n$ lines contains the beginning and the length of the $i(1\le i\le n)$ film — two integers in format $h$ hours $m(0\le h\le 23,0\le m\le 59)$ minutes.

Output

Print the maximum number of visited sessions.

Examples