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

int main() 
{
    int n;
    cin >> n;
    string s;
    cin >> s;
    int i,b[4]={0};
    for(i=0;i<n;i++)
    {
        if(s[i]>='a' && s[i]<='z')
            b[0]=1;
        if(s[i]>='A' && s[i]<='Z')
            b[1]=1;
         if(s[i]>='0' && s[i]<='9')
            b[2]=1;
        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]=='@'||s[i]=='"')
            b[3]=1;
    }
    int x;
    x=4-(b[0]+b[1]+b[2]+b[3]);
    if(n<6)
    {
        int y=6-n;
        if(x>y)
            cout<<x<<endl;
        else 
            cout<<y<<endl;
    }
    else 
    {
    cout<<x<<endl;
    }
    return 0;
}