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

int main(void)
{
  ifstream fi;
  string s;
  cout << "Anna tiedoston nimi>"; getline(cin,s);
  fi.open(s.c_str());

  int i,n=0;
  double summa=0,ka;

  while ( 1 ) {
    fi >> i;
    if ( !fi ) break;
    summa += i;
    n++;
  }
  if ( n == 0 ) { return 1; }
  ka = summa/n;

  cout.precision(3); cout.setf(ios::fixed || ios::showpoint);
  cout << ka << "\n";
  return 0;
}