Codeforce B. Polycarp and Letters

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

input

12
zACaAbbaazzC

output

input

3
ABC

output

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.

此题求2个大写字母间小写字母不同的个数；

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;

int n,m,a[128],maxx,ans;
char s[1008];

int main(){
    scanf("%d",&n);
    scanf("%s",s);
    maxx=0; ans=0;
    for(int i=0;i<n;i++){
        if(s[i]>='A'&&s[i]<='Z'){
            memset(a,0,sizeof(a));
            ans=max(ans,maxx);
            maxx=0;
        }else{
            if(!a[s[i]]){
                a[s[i]]=1;
                maxx++;
            }
        }
    }
    ans=max(maxx,ans);
    printf("%d",ans);
}