program ballc;
var
  n,i,j:longint;
  temp,min:double;
  sz:array[1..10000]of longint;
  d:array[1..10000,1..2]of longint;
begin
  assign(input,'ballc.in');
  assign(output,'ballc.out');
  reset(input);
  rewrite(output);
  readln(n);
  for i:=1 to n do
    read(sz[i]);
  for i:=1 to n do
    readln(d[i,1],d[i,2]);
  min:=2000000000;
  for i:=1 to n do
  begin
    temp:=0;
    for j:=1 to n do
      temp:=temp+sz[j]*(abs(d[j,1]-d[i,1])+abs(d[j,2]-d[i,2]));
    if temp<min then min:=temp;
  end;
  writeln(min:0:2);
  close(input);
  close(output);
end.