#include <iostream>

using namespace std;

int n;

int cifre ( int n ){

    int numere = 0, elemente = 0, i = 0, v[100];

    while ( n ){
        i = n % 10;
        elemente++;
        v[i]++;
        n /= 10;
    }

    for ( int i = 1; i <= elemente; i++ ){
        if ( v[i] == 1 )
            numere++;
    }

    return numere;

}

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