#include <iostream>
#include <fstream>
#include <stdio.h>

using namespace std;

ofstream g("date.out");

char c;
int cuv,lit,q;

int main()
{
    FILE *fp;

    fp = fopen("date.in", "r");

    while((c = fgetc(fp)) != EOF){
        if(int(c)>=65 && int(c)<=90 || int(c)>=97 && int(c)<=122){
                lit++;
            }

        if((int(c)<65 || (int(c)>90 &&int (c)<97)) || (int(c)>122)){
            if(q>=65 && q<=90 || q>=97 && q<=122){
                cuv++;
            }
        }
        q=int(c);
    }

    g<<lit/cuv;
    fclose(fp);

    return 0;
}