#include <iostream>

using namespace std;

int n;

int cifre ( int n ){

    int numere = 0, v[10];
    for ( int i = 1; i <= 9; i++ ) v[i] = 0;
    while ( n ){
       v[ n % 10]++;
        n /= 10;
    }

    for ( int i = 0; i <= 9; i++ )
        if ( v[i] == 1 )
        numere++;


    return numere;

}

int main()
{
    cin >> n;
    cout << cifre(n);
    return 0;
}