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


int main() {
    int n;
    cin>>n;
    string str;
    cin>>str;
    int u=0,l=0,d=0,s=0,min=0;
    if(n<6)
    {
        int m=0;
        for(int i=0;i<n;i++)
        {
            if(str[i] >=65 && str[i] <= 90)
                u++;
            if(str[i] >= 97 && str[i] <= 122)
                l++;
            if(str[i]>=33 && str[i] <=43)
                s++;
            if(str[i] >= 49 && str[i] <=57)
                d++;
        }
         if(d==0)m++;
        if(u==0)m++;
        if(l==0)m++;
        if(s==0)m++;
        if(m < 6-n)
        {
            min=6-n;
        }
        else{
        min=m;
        }
        
    }
    else
    {
        for(int i=0;i<n;i++)
        {
            if(str[i] >=65 && str[i] <= 90)
                u++;
            if(str[i] >= 97 && str[i] <= 122)
                l++;
            if(str[i]=='!' || str[i] =='@' || str[i] =='#' || str[i] =='$' || str[i] =='%'|| str[i] =='^'|| str[i] =='&'|| str[i] =='*'|| str[i] =='('|| str[i] ==')'|| str[i] =='-'|| str[i] =='+')
                s++;
            if(str[i] >= 48 && str[i] <=57)
                d++;
        }
        if(d==0)min++;
        if(u==0)min++;
        if(l==0)min++;
        if(s==0)min++;
    }
    cout<<min;
    return 0;
}