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

#define MAXN 101
#define INF 0x3f3f3f3f
typedef long long LL;

int n;
char s[MAXN];

int main()
{
    int i, flag = 0, ans = 0;
    scanf("%d %s", &n, s);
    for(i = 0; i < n; ++i){
        if(s[i] >= '0' && s[i] <= '9') flag |= 1;
        if(s[i] >= 'a' && s[i] <= 'z') flag |= 2;
        if(s[i] >= 'A' && s[i] <= 'Z') flag |= 4;
        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] == '+')
            flag |= 8;
    }
    flag ^= 15;
    for( ; flag; ++ans, flag -= flag & -flag);
    printf("%d\n", max(ans, 6 - n));
	return 0;
}