#include <cmath>
#include <cstdio>
#include <vector>
#include<string>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    string s;
    int n;
    cin>>n;
    cin>>s;
    int i;
    int c1=0,c2=0,c3=0,c4=0;
   
    for(i=0;i<n;i++)
    {
        if(s[i]>='a'&&s[i]<='z')
            c1++;
        else if(s[i]>='A'&&s[i]<='Z')
            c2++;
        else if(s[i]>='0'&&s[i]<='9')
            c3++;
        else if(s[i]=='!'||s[i]=='@'||s[i]=='#'||s[i]=='$'||s[i]=='^'||s[i]=='%'||s[i]=='&'||s[i]=='*'||s[i]=='('||s[i]==')'
                ||s[i]=='-'||s[i]=='+')
                c4++;
    }
    int l=0;
    if(c1==0)
        l++;
    if(c2==0)
        l++;
    if(c3==0)
        l++;
    if(c4==0)
        l++;
    
    if(n+l>6)
        cout<<l;
    else if(l>6-n)
        cout<<l;
    else
        cout<<6-n;
    return 0;
}