var q,w,e,r,t,y,u,i,o,a,s,d,f,g,h,j,k,z,x,c,v,b,n,m:integer;
begin
readLn(q,w,e,r,t,y,u,i,o,a,s,d,f,g,h,j,k,z,x,c,v,b,n,m);
writeLn((q+w+e+r+t+y+u+i+o+a+s+d+f+g+h+j+k+z+x+c+v+b+n+m)/19:0:0)
end.

var i, n: integer;
  sum, x: real;
begin
  write('n = '); readln(n);
  sum := 0.0;
  for i := 1 to n do
    begin
      write(i);  
      readln(x);
      sum := sum + x
    end;
  writeln((sum/n):8:5)
end.

program p4;
      var a,S:integer;
            A:array [1..19] of integer;
            b:real;
begin
      randomize
        for a:= 1 to 19 do
         begin
             A [a]:= random (5)+1;
                writeln (A [a]);
         end;
      S:=0;
      for a:= 1 to 19 do
      A:= a+A [a];
      b:=s/19
      writeln (b);
end.