#include <fstream.h>
#include <string.h>
char s[3000005];
long long nc,nt,nr,i,sw;

int main()
{
 ifstream fin("text.in");
  fin.get(s,3000005,'\n');
  i=0;
  while(i<strlen(s))
  {
   while((s[i]<'a' || s[i]>'z') && (s[i]<'A' || s[i]>'Z') && i<strlen(s))
    i++;
   sw=0;
   while((s[i]>='a' && s[i]<='z') || (s[i]>='A' && s[i]<='Z') && i<strlen(s))
   {
    i++;
    nr++; sw=1;
   }
   nt+=nr;
   if(sw)
    nc++;
   nr=0;
  }

 fin.close();

 ofstream fout("text.out");
  fout<<nt/nc;
 fout.close();
return 0;
}