#include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
int main()
{
	char a[1004],*p;int i,nr=0,s=0;
	freopen("text.in","r",stdin);freopen("text.out","w",stdout);
	cin.get(a,1004);
	p=strtok(a," ,!:;.(){}[1230654789]'-?");
	while(p)
	{
		nr++;
		s+=strlen(p);
		p=strtok(0," -.,:?{}['1234567890]!;()");
	} 
	cout<<s/nr;
	
}