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

int n;
bool s,u,d,sp;
string str;

int main()
{
    cin>>n>>str;
    for(int i=0; i<n; i++)
    {
        if(str[i]<='9' && str[i]>='0')
            d=true;
        else if(str[i]<='Z' && str[i]>='A')
            u=true;
        else if(str[i]<='z' && str[i]>='a')
            s=true;
        else
            sp=true;
    }
    int need=s+u+d+sp;
    need=4-need;

    if(need+n>=6)
        cout<<need<<endl;
    else
        cout<<6-n<<endl;
}