#include<bits/stdc++.h>
using namespace std;
int main(){
	string s;
	int ans=0;
	cin>>s;
	for(int i=0;i<s.length();i++){
		if((s[i]>='a'&&s[i]<='z')||(s[i]>='A'&&s[i]<='Z')||(s[i]>='0'&&s[i]<='9')){
			ans++;
		}
	}
	cout<<ans;
}