import java.util.Scanner;
 
public class Main
{
	public static void main (String[] args)
	{
		long n;
		int differentDigitsCount = 0;
		int[] digitsCount = new int[10];
		Scanner scanner = new Scanner(System.in);
 
		n = scanner.nextLong();
 
		while (n!=0)
		{
			digitsCount[(int)(n%10)]++;
			n/=10;
		}
		for (int i = 0; i < 10; i++)
		{
			if (digitsCount[i] > 0) differentDigitsCount++;
		}
 
		System.out.println(differentDigitsCount);
	}
}

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MQ==

1