#include<stdio.h>
#include<string.h>
int main()
{
   long int num=0,s=0,s2,v,i,k,c1;
   char c[100000];
   freopen ("text.in","r",stdin);
   freopen ("text.out","w",stdout);
   v=0;
   while (!feof(stdin))
	 {
	   scanf("%s",c);
	   s=strlen(c);
	   for (k=1; k<=s; k++)
	   { c1=int(c[k]);
	   for (i='a'; i<='z';i++)
	       if (c1==i) {v++; break;}
	   if (v==0)
	   for (i='A'; i<='Z';i++)
	       if (c1==i) {v++; break;}
	   }
	   num++;
	 }
   s2=v/num;
   printf("%ld",s2);
   return 0;
}