#include<fstream.h>
int main()
{ifstream f("text.in");
 ofstream g("text.out");
 char car,car2;
 //float rasp;
 unsigned long cont=0,cuv=0;
 f.get(car);
 if(((car>='a')&&(car<='z'))||((car>='A')&&(car<='Z'))) cont++;
 while(!f.eof())
  {f.get(car2);
   if(((car2>='a')&&(car2<='z'))||((car2>='A')&&(car2<='Z'))) cont++;
    else if(((car>='a')&&(car<='z'))||((car>='A')&&(car<='Z'))) cuv++;
   car=car2;
  }
  if(!cuv) g<<0<<'\n';
  else {//rasp=cont/cuv;
	g<<cont/cuv<<'\n';
       }
 g.close();
return 0;
}