#include <iostream>
#include <fstream>
#include <string>
using namespace std;
 
string s;
int main()
{
    int i,j,cuvinte=0,litere=0;
    char c;
    ifstream in("text.in");
    ofstream out("text.out");
    while (in>>c)
    {
        s=s+c;
    }
    for (i=0; i<s.size();i++)
    {
        if ( (s[i]>='a' && s[i]<='z') || (s[i]>='A' && s[i]<='Z') )
        {
            for (j=i; j<s.size();j++)
            {
                if ( (s[j]>='a' && s[j]<='z') || (s[j]>='A' && s[j]<='Z') )
                {
                    litere++;
                }
                else
                {
                    i=j;
                    cuvinte++;
                    break;
                }
            }
        }
    }
    if (cuvinte!=0)
        out<<litere/cuvinte;
    else
        out<<litere;
}