#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n;
	cin>>n;
	string s;
	cin>>s;
	int a[4]={0};
	int res1=0,res2=0;
	
	
	for(int i=0;i<n;i++)
	{
	if((s[i]>='a'&&s[i]<='z'))
	a[0]++;
	if((s[i]>='A'&&s[i]<='Z'))
	a[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]=='+')
	a[2]++;
	if(s[i]>='0'&&s[i]<='9')
	a[3]++;
	}

if(n>=6)
{
	for(int i=0;i<4;i++)
	if(a[i]==0)
res1++;
cout<<res1;
}
if(n<6)
{
	int z=6-n;
		for(int i=0;i<4;i++)
	if(a[i]==0)
res2++;
	if(res2>z)
	cout<<res2;
	else
	cout<<z;
	
	
}
}