# include <fstream>
# include <string.h>

using namespace std;

int main ()
{
    char t[1001],sep[]=" !#$%^&*()-=+',./\0123456789?@",*p;
    unsigned lit=0,cuv=0;
    ifstream fin ("text.in");
    ofstream fout("text.out");
fin.get(t,1001);
 for(int i = 0; i < strlen(t); i++)
       {if((t[i] >= 'a' && t[i]<='z')||(t[i]>='A'&&t[i]<='Z'))
        lit++;
           }
           p=strtok(t,sep);

    while(p)
    {
        cuv++;
        p=strtok(NULL,sep);
    }
   if(cuv!=0)
    fout<<lit/cuv;
   else
    fout<<0;
   fin.close();
   fout.close();
    return 0;
}