#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;
ifstream f("text.in" );
ofstream g("text.out");

char text[1000031];

int NrTotalLitere, NrLit, NrCuvinte;



#define COND_LIT(i) ( ('a'<=text[i] && text[i]<='z') or ('A'<=text[i] && text[i]<='Z') )


int main()
{
    f.getline(text,1000500); text[strlen(text)] = ' ';

    for ( int i=0 ; text[i] ; i++ )
    {
        if ( !COND_LIT(i) ) {
            if ( NrLit ) {
                NrTotalLitere += NrLit;
                NrLit = 0; NrCuvinte++;
            }
        } else NrLit++;
    }
    g << NrTotalLitere/NrCuvinte;
}