#include <iostream> 
#include <cmath> 
#include <cstring> 
#include <string> 
#include <cstdio> 
#include <cstdlib> 
#include <iomanip> 
#include <set> 
#include <algorithm> 
#define MAXN 0x7fffffff 
using namespace std; 
string str;
int a,s;
bool bo[34];
int main(void) 
{    
    freopen("expression.in","r",stdin); 
    freopen("expression.out","w",stdout); 
	cin>>str;
	for (a=0;a<str.length();a++)
		if ((str[a]>='a')&&(str[a]<='z')) bo[str[a]-'a']=true;
			else if (str[a]=='+') bo[26]=true;
				else if (str[a]=='*') bo[27]=true;
					else if (str[a]=='#') bo[28]=true;
						else if (str[a]=='@') bo[29]=true;
							else if (str[a]=='$') bo[30]=true;
								else if (str[a]=='%') bo[31]=true;
									else if (str[a]=='^') bo[32]=true;
										else bo[33]=true;
	for (a=0;a<34;a++)
		if (bo[a]==true) s++;
	cout<<s;
    fclose(stdin); 
    fclose(stdout); 
    return 0; 
}