program subway;
const
 maxn=202;
type
 node=record
       x,y:longint;
      end;
var
 map:array[1..maxn,1..maxn]of longint;
 dist:array[1..maxn] of longint;
 jiedian:array[1..maxn]of node;
 f:array[1..maxn]of boolean;
 i,j,t,s:integer;
 s1,s2:real;
 tex:text;
function juli(i,j:integer):longint;
 var
  x3,y3,x4,y4:longint;
 begin
  with jiedian[i] do
   begin
    x3:=x;
    y3:=y;
   end;
  with jiedian[j] do
   begin
    x4:=x;
    y4:=y;
   end;
  juli:=round(sqrt(sqr(x3-x4)+sqr(y3-y4)));
 end;
procedure init;
 var
  a,b:longint;
 begin
  assign(tex,'subway.in');
  reset(tex);
  s1:=2000/3;
  s2:=500/3;
  fillchar(map,sizeof(map),0);
  for i:=1 to 2 do
    with jiedian[i] do
     read(tex,x,y);
  readln(tex);
  t:=2;
  s:=t;
   while not eof(tex) do
    begin
       read(tex,a,b);
       while not eoln(tex) do
        begin
         inc(t);
         with jiedian[t] do
          begin
           x:=a;
           y:=b;
           if t<>s+1 then
            begin
             map[t,t-1]:=round(juli(t,t-1)/s1);
             map[t-1,t]:=map[t,t-1];
            end;
          end;
         read(tex,a,b);
        end;
        s:=t;
        readln(tex);
   end;
  for i:=1 to t do
   for j:=1 to t do
     if map[i,j]=0 then
        begin
         map[i,j]:=round(juli(i,j)/s2);
         map[j,i]:=map[i,j];
        end;
  for i:=1 to maxn do
    dist[i]:=maxint;
  dist[1]:=0;
  fillchar(f,sizeof(f),true);
  f[1]:=false;
  close(tex);
 end;
procedure dijkstra(n:integer);
 var
  min,w:integer;
 begin
   w:=1;
   for i:=1 to n-1 do
    begin
     min:=maxint;
     for j:=1 to n do
         if (dist[j]<min)and f[j] then
          begin
           min:=dist[j];
           w:=j;
          end;
     for j:=1 to n do
       if (dist[w]+map[w,j]<dist[j])and f[j] and(map[w,j]<>maxint)
        then
         dist[j]:=dist[w]+map[w,j];
     f[w]:=false;
    end;
 end;
begin
 init;
 dijkstra(t);
 writeln(dist[2]);
 readln;
end.