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


int main() {
    int n,i,b=0,c=0,d=0,e=0,f=0,g=0;
    char a[20];
    cin>>n;
    cin>>a;
    for(i=0;i<n;i++)
    { if(isalpha(a[i]))
    { if(islower(a[i]))
      b=1;
    else
    c=1;
    }
    else if(isdigit(a[i]))
        d=1;
    else
    e=1;
    }
    if(n<6)
        f=6-n;
    g=4-b-c-d-e;
    if(f>g)
        cout<<f;
    else
        cout<<g;
    return 0;
}