#include <iostream>
#include <fstream>
using namespace std;
ifstream in("text.in");
ofstream out("text.out");
int cuv,rez,nrc;
char a;
int main()
{
    while(in>>noskipws>>a)
    {
        if(isalpha(a))
            cuv++;
        else
        {
            if(cuv!=0)
        {
            rez+=cuv;
            cuv=0;
            nrc++;
        }
        }
}
    out<<rez/nrc;
    return 0;
}