#include<iostream>
#include<fstream>
using namespace std;
int nrc,nrl,i;
string s;
int main()
{
    ifstream f("text.in");
    ofstream g("text.out");
    while(f>>s)
    {  nrc++;
        nrl+=s.length();
        for(i=0;i<s.size();i++)
     if(s[i]=='-'||s[i]==','||s[i]=='?'||s[i]=='!'||s[i]=='.'||s[i]=='"')
       if(((s[i-1]>='a'&&s[i-1]<='z')||(s[i-1]>='A'&&s[i-1]<='A'))&& ((s[i+1]>='a'&&s[i+1]<='z')||(s[i+1]>='A'&&s[i+1]<='A')))  nrc++;
    }
    g<<nrl/nrc;
    return 0;
}