var s:string;
    f:text;
    n,nr,sum,nu,i:integer;

begin
     assign(f,'text.in');
     reset(f);
     readln(f,s);
     close(f);

     n:=length(s);
     i:=0;
     nr:=2;
     sum:=0;
     nu:=0;
      for i:=1 to n do if s[i]=' ' then nr:=nr+1;
      for i:=1 to n do if ((s[i]>='A') and (s[i]<='Z'))
                                      or( (s[i]>='a') and (s[i]<='z')) then nu:=nu+1;
      assign(f,'text.out');
      rewrite(f);

      writeln(f,nu/nr:0:0);
      close(f);
end.