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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int n,i,b[4]={0},c=0;string s;
    cin>>n;
    cin>>s;
    for(i=0;i<n;i++)
    {
        if(s[i]>=48&&s[i]<=57)
            b[0]++;
        else if(s[i]>=65&&s[i]<=90)
            b[1]++;
        else if(s[i]>=97&&s[i]<=122)
            b[2]++;
 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]=='+')
            b[3]++;
    }
    for(i=0;i<=3;i++)
    { if(b[i]==0)
            c++;}
    if(n+c>=6)
        cout<<c;
    else
        cout<<6-n;
    return 0;
}