#include<stdio.h>
#include<string.h>
int main()
{
    FILE *f=fopen("text.in","r"),*g=fopen("text.out","w");
    char a[100000],*p;
    int i=0,n,cuv=0,lit=0,valid;
    while(!feof(f))
     {  fscanf(f,"%c",&a[i]);i++; }

    p = strtok (a," ,.-:!?';()`}{[]|+=_");
    while (p != NULL) {
          cuv++; lit+=strlen(p);
          i=strlen(p)-1;
//          fprintf(g,"%c\n",p[i]);
          valid=1;
          while(valid!=0){
                          if(!((p[i]>='a')&&(p[i]<='z'))||((p[i]>='A')&&(p[i]<='Z')))lit--; 
                          else valid=0;
                          i--;
                          }      
//          fprintf(g,"%d ",strlen(p));
          p = strtok (NULL, " ,.-");
          }
    
//    fprintf(g,"\n%d %d",cuv,lit);
    fprintf(g,"%d",(lit/cuv));
    return 0;
}