#include <iostream>
#include <set>
#include <cstring>
#include <cctype>
using namespace std;
int main() {
char str[100];
cin >> str;
int n = strlen(str);
set<char> s;
for (int i = 0; i < n; i++) {
if (isdigit(str[i])) {
s.insert(str[i]);
}
}
cout << s.size();
return 0;
}
I2luY2x1ZGUgPGlvc3RyZWFtPgojaW5jbHVkZSA8c2V0PgojaW5jbHVkZSA8Y3N0cmluZz4KI2luY2x1ZGUgPGNjdHlwZT4KCnVzaW5nIG5hbWVzcGFjZSBzdGQ7CgppbnQgbWFpbigpIHsKICAgIGNoYXIgc3RyWzEwMF07CiAgICBjaW4gPj4gc3RyOwogICAgaW50IG4gPSBzdHJsZW4oc3RyKTsKICAgIHNldDxjaGFyPiBzOwogICAgZm9yIChpbnQgaSA9IDA7IGkgPCBuOyBpKyspIHsKICAgICAgICBpZiAoaXNkaWdpdChzdHJbaV0pKSB7CiAgICAgICAgICAgIHMuaW5zZXJ0KHN0cltpXSk7CiAgICAgICAgfQogICAgfQogICAgY291dCA8PCBzLnNpemUoKTsKICAgIHJldHVybiAwOwp9