Codeforces 443A

#include <stdio.h>
#include <string.h>
 
#define Maxsize 3200
 
int main()
{
	int letter[30];
	memset(letter, 0, sizeof(letter));
	char line[Maxsize];
	gets(line);
	int length;
	length=strlen(line);
	int i=1;
	while(i<length)
	{
		letter[line[i]-97]++;
		i+=3;
	}
	int Count=0;
	for(i=0; i<26; ++i)
	{
		if(letter[i]!=0)
			++Count;
	}
	printf("%d\n", Count);
	return 0;
}