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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int n,a=0,b=0,c=0,d=0,i,f=0;  string s;   cin>>n;   cin>>s;
    for(i=0;i<n;i++)
    {
        if(s[i]>=65&&s[i]<=90)   {a++;}
        else if(s[i]>=97&&s[i]<=122)   {b++;}
       else if(s[i]>='0'&&s[i]<='9')   {c++;}
        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]=='+')    {d++;}
    }
    if(n>=6&&a!=0&&b!=0&&c!=0&&d!=0)   {cout<<"0"<<endl;}
    else if(n<=2)      {cout<<6-n<<endl;}
    else if(n>2)
    {
        if(a==0)  {f++;}
        if(b==0)  {f++;} 
        if(c==0)  {f++;} 
        if(d==0)  {f++;} 
        if(f+n>=6)   {cout<<f<<endl;}
        else         {cout<<6-n<<endl;}
    }
    return 0;
}