#include <bits/stdc++.h>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int n;
    cin>>n;
    string s;
    cin>>s;
    int l = s.length(),i;
    int a[4]={0};
    //int num=0,lc=0,uc=0,spl=0;
    for(i=0;i<l;i++)
    {
        if(s[i] >= '0' && s[i] <= '9' )
            a[0]++;//num++;
        else if(s[i] >= 'A' && s[i] <='Z')
            a[1]++;//uc++;
        else if(s[i]>='a' && s[i]<='z')
            a[2]++;//lc++;
        else
            a[3]++;//spl++;
    }
    
    int count=0;
    for(i=0;i<4;i++)
        if(a[i]==0)
            count++;
    if(l>=6)
        cout<<count<<endl;
    else if(l<6 && l+count>=6)
        cout<<count<<endl;
    else if(l<6 && l+count<6)
        cout<<count+(6-l-count)<<endl;
    
    return 0;
}