#include <iostream>
#include <cstring>
#include <set>
using namespace std;
int main() {
set<char> k;
set<char>::iterator iter;
char s[101];
cin >> s;
for(int i = 0; i < strlen(s); i++){
k.insert(s[i]);
}
cout << k.size();
return 0;
}
I2luY2x1ZGUgPGlvc3RyZWFtPgojaW5jbHVkZSA8Y3N0cmluZz4KI2luY2x1ZGUgPHNldD4KdXNpbmcgbmFtZXNwYWNlIHN0ZDsKIAppbnQgbWFpbigpIHsKCXNldDxjaGFyPiBrOwoJc2V0PGNoYXI+OjppdGVyYXRvciBpdGVyOwoJY2hhciBzWzEwMV07CgljaW4gPj4gczsKCWZvcihpbnQgaSA9IDA7IGkgPCBzdHJsZW4ocyk7IGkrKyl7CgkJay5pbnNlcnQoc1tpXSk7Cgl9Cgljb3V0IDw8IGsuc2l6ZSgpOwoJcmV0dXJuIDA7Cn0=