//
#include <bits/stdc++.h>
#include <string.h>
using namespace std;
char a[256]; 
int main()
{
	int count;
	gets(a);
	for (int i=0;i<strlen(a);i++)
		if (a[i]<='9'&&a[i]>='0') count++;
	cout<<count; 
	return 0
}