Since attending Seoul Cyber University

Time limit1sMemory limit512 MB

Summary

Given a lowercase string with spaces, commas, and periods, the task counts how often the most frequent letter appears.

Level: Easy1 of 10
Topics: String, Hash map
Solved: No attempts yet

Problem

My era of success began after attending Seoul Cyber University. More companies have come looking for me since I attended Seoul Cyber University. My life changed after I attended Seoul Cyber University. The strategy that changes the future. Seoul Cyber University

The Seoul Cyber University logo song is very, very famous for its catchy melody. Professor Noh and Professor Cheon, who analyzed data at the Big Data and AI Center, heard the logo song playing from somewhere and wondered how many times the most frequently used letter appears.

Print how many times the most frequently used letter appears, on behalf of the two professors who are addicted to the melody.

Input

The first line contains the length $N$ of the logo song. $(1 \le N \le 10^5)$

The second line gives the logo song as a single string. The string is the English translation of the Seoul Cyber University logo song, repeated. It consists only of lowercase letters, spaces, commas, and periods. The string never ends with a space.

Output

Print one line with the number of occurrences of the most frequent letter. Spaces, commas, and periods are not counted.

Hint

The English translation of the logo song is "my era of success began with seoul cyber university, since attending seoul cyber university, more companies have been seeking me out, my life has changed since i went to seoul cyber university, the strategy that changes the future, seoul cyber university. ".

Examples3

Example 1

Input

255
my era of success began with seoul cyber university, since attending seoul cyber university, more companies have been seeking me out, my life has changed since i went to seoul cyber university, the strategy that changes the future, seoul cyber university.

Expected output

Example 2
Input
```
1
m
```
Expected output
```
1
```

Example 3

Input

51
my era of success began with seoul cyber university

Expected output