Merkkijono

#include <bits/stdc++.h>
#define ll long long
#define INF 999999999
#define N (1<<17)
#define M 1000000007

using namespace std;

int main () {
  string s;
  cin>>s;
  set<char> c;
  for (char i : s) c.insert(i);
  cout<<c.size()<<endl;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED