#include <stdio.h>
#include <string.h>

FILE *intrare, *iesire;

char text[1050000], *p, sep[]=" `~1234567890!{@#$%^&**()-}|\":+?=><,./;[]'\\";
int nrlitere, nrcuv;

void citire();
int nrLitere(char *p);

int main()
{
 citire();

 return 0;
}

void citire()
{
 intrare = fopen("text.in", "r");

 fgets(text, 1050000, intrare);

 p = strtok(text, sep);

 while(p)
 {
   nrcuv++;
   nrlitere += nrLitere(p);
   p = strtok(NULL, sep);
 }

 iesire = fopen("text.out", "w");

 fprintf(iesire, "%d", nrlitere/nrcuv);

 fclose(iesire);
 fclose(intrare);
}

int nrLitere(char *p)
{
  int nr=0, i, n;

  n = strlen(p);

  for(i=0; i<n; i++)
  {
   if((*p>='a' && *p<='z') || (*p>='A' && *p<='Z'))
     nr++;
  }

  return nr;
}