#include<bits/stdc++.h>
using namespace std;
int n,cnt=0;
int main()
{
	string s;
	cin>>s;
	n=s.size();
	for(int i=0;i<=n-1;i++){
		if(s[i]>='A'&&s[i]<='Z'||s[i]>='a'&&s[i]<='z')
		{
			cnt=cnt+1;
		}
	}
	cout<<cnt;
	return 0;
}