#include <fstream.h>
#include <ctype.h>

#define MAX 1048576

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

int main(){
    char s[MAX];
    long int i; long double c,l;c=0; l=0;
    while(!f.eof()){
    f.get(s,MAX);
    long int a=strlen(s);
    
    for(i=0; i<a; i++)
    {
             if(isalpha(s[i]))l++;
             if(!(isalpha(s[i])))if(isalpha(s[i-1]))c++;
             }
             if(isalpha(s[a-1]))c++;}
             g<<int(l/c);
    }