#include <iostream>
#include <string.h>
#include <stdio.h>
#include <fstream>
using namespace std;


int main()
{
    ifstream fin("text.in");
    ofstream fout("text.out");
     char s[100],*cuv;
    int n,i,lit=0,cuvinte=0;
    fin.getline(s,100);
    n=strlen(s);
    for(i=0;i<=n-1;++i) if(isalpha(s[i]))lit++;
    strtok(s," ,.-");
    while(cuv!=NULL)
    {
        cuvinte++;
        cuv= strtok(NULL, " ,.-");
    }
    fout<<lit/cuvinte;

    return 0;
}