#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef long double LD;
typedef pair<LL,LL> PLL;
typedef pair<LD,LD> PDD;
typedef pair<int,int> PII;
typedef pair<PII,PII> PPII;
#define PRINT(a) cerr<<#a<<" = "<<(a)<<'\n'
#define B_E(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define S second
#define F first






const clock_t MAXT = (100*CLOCKS_PER_SEC)/1000;
const int   PX[8] = {1,0,-1,0,  1,1,-1,-1},
            PY[8] = {0,1,0,-1,  -1,1,1,-1},
            N = 1e5 + 10,
            INF = 1e9,
            MOD = 1e9 + 7;
const LL    INFL = 1e18,
            MODL = 1e9 + 7;
const LD    EPS = 1e-9;

inline int rnd(int l = 0, int r = INF) {
    unsigned ans = rand();
    ans = (ans<<8) ^ rand();
    ans = (ans<<8) ^ rand();
    ans = (ans<<8) ^ rand();
    ans %= r-l+1;
    return int(ans + l);
}




string s,numbers,lower_case,upper_case,special_characters;
int n,x[250];
set<int> ss;


int main()
{ 

    numbers = "0123456789";
    lower_case = "abcdefghijklmnopqrstuvwxyz";
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    special_characters = "!@#$%^&*()-+";


    for (char i:numbers) x[i] = 1;
    for (char i:lower_case) x[i] = 2;
    for (char i:upper_case) x[i] = 3;
    for (char i:special_characters) x[i] = 4;

    cin>>n;
    for (int i=0; i<n; ++i) {
        char h; cin>>h;
        ss.insert( x[h] );
    }


    int s = n + 4 - ss.size();
    if ( s < 6 )
        s = 6;
    cout<<s-n;













}