#include <bits/stdc++.h>

using namespace std;

bool spe(char c)
{
    if(c=='!'||c=='@'||c=='#'||c=='$'||c=='%'||c=='^'||c=='&'||c=='*'||c=='('||c==')'||c=='-'||c=='+')
        return true;
    return false;
}
int minimumNumber(int n, string p) {
    // Return the minimum number of characters to make the password strong
    int co=0;
    int a=0;
    int b=0;
    int c=0;
    int d=0;
   
    for(int i=0;i<n;i++)
    {
        if(p[i]>='0'&&p[i]<='9')
            a=1;
        if(p[i]>='a'&&p[i]<='z')
            b=1;
        if(p[i]>='A'&&p[i]<='Z')
            c=1;
        if(spe(p[i]))
            d=1;
        
        
    }
    if(a==0)
        co+=1;
    if(b==0)
        co+=1;
     if(c==0)
        co+=1;
    if(d==0)
        co+=1;
    int ans=6-(n+co);
    if(ans<0)
        return co;
    else
        return 6-n;
    
}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}