#include<iostream> 
using namespace std;
int main(){ //C++L17 字符统计 
	string s; int ans=0;
	cin>>s;
	for(int i=0;i<s.length();i++)
		if(s[i]>='a' and s[i]<='z')
			ans++;
	cout<<ans;
	return 0;
}