codefoeces 864B

B. Polycarp and Letters

time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

Polycarp loves lowercase letters and dislikes uppercase ones. Once he got a string s consisting only of lowercase and uppercase Latin letters.

Let A be a set of positions in the string. Let's call it pretty if following conditions are met:

• letters on positions from A in the string are all distinct and lowercase;
• there are no uppercase letters in the string which are situated between positions from A (i.e. there is no such j that s[j] is an uppercase letter, and a1 < j < a2 for some a1 and a2 from A).

Write a program that will determine the maximum number of elements in a pretty set of positions.

Input

The first line contains a single integer n (1 ≤ n ≤ 200) — length of string s.

The second line contains a string s consisting of lowercase and uppercase Latin letters.

Output

Print maximum number of elements in pretty set of positions for string s.

Examples

input

11
aaaaBaabAbA

output

2

input

12
zACaAbbaazzC

output

3

input

3
ABC

output

0

Note

In the first example the desired positions might be 6 and 8 or 7 and 8. Positions 6 and 7 contain letters 'a', position 8 contains letter 'b'. The pair of positions 1 and 8 is not suitable because there is an uppercase letter 'B' between these position.

In the second example desired positions can be 7, 8 and 11. There are other ways to choose pretty set consisting of three elements.

In the third example the given string s does not contain any lowercase letters, so the answer is 0.

 这道题一直理解不了题意，看了代码才知道到底啥意思。

就是先找出每一段小写字母里的不同元素有多少个，再输出其中最大那一段的值。

#include<cstdio>
#include<cmath>
#include<iostream>
#include<vector>
#include<set>
#include<sstream>
#include<algorithm>
#include<string>
#include <cstring>
using namespace std;
const int maxn = 111;
int nu[maxn];
set<int> st;
string s;
int main() {
    ios::sync_with_stdio(false);
    int n;
    int maxx = 0;
    cin>>n>>s;
    s+="A";
    for(int i = 0; i <= n; i++) {
       // cout<<st.size()<<endl;
        if(s[i] >= 'a' && s[i] <= 'z') st.insert(s[i]);
        else maxx = max(maxx,(int)st.size()),st.clear();
    }
    cout<<maxx<<endl;
    return 0;
    
}