#include <stdio.h>

int main()
{   /* problema test, infoarena */
 	int lc, nrc, lt;
 	char c;
 	FILE *f=fopen("text.in","rt");
 	if (!f) return 1;
 	nrc=lc=lt=0;
 	fscanf(f,"%c", &c);
 	while (c!='\n')
 	{
	 	  if ('a'<=c && c<='z' || 'A'<=c && c<='Z') lc++;
	 	   else 
		 	if (lc!=0)
			 	{
	 	           lt+=lc; 
			 	   lc=0;
			 	   nrc++;
		        }
        fscanf(f,"%c",&c);
    }
    fclose(f);
    f=fopen("text.out","wt");
    fprintf(f,"%i\n",lt/nrc);
    fclose(f);
 	return 0;
}