#include<stdio.h>

char c,c2;
long long a,b;


int main(){

FILE *f=fopen("text.in","r");

fscanf(f,"%c",&c);

 if(c>=65&&c<=90||c>=97&&c<=122){
 b++;
 a++;
 }

  while(!feof(f)){

  fscanf(f,"%c",&c2);

    if(c2>=65&&c2<=90||c2>=97&&c2<=122){
      a++;

      if(!(c>=65&&c<=90||c>=97&&c<=122)){
      b++;
      }

    }

  c=c2;

  }

fclose(f);


 FILE *g=fopen("text.out","w");
 fprintf(g,"%lld",a/b);
 fclose(g);

return 0;
}