{$MODE OBJFPC}
{$R-, Q-}
{$M 10000111}

uses math;

const
  fin = '';
  fou = '';
  MAXN = 10101;
  oo = 1000111000;

type
  pnode = ^tnode;
  tnode = record
    v : longint;
    next : pnode;
  end;

var
  c, t : array[1..MAXN] of longint;
  //adj : array[1..MAXN, 1..MAXN] of longint;
  maxt : longint;
  cur, cc : longint;
  matchx, matchy, free : array[1..MAXN] of longint;
  a : array[1..MAXN] of pnode;
  n : longint;
  res : longint;


function find(u:longint) : boolean;
var
  v : longint;
  p : pnode;
begin
  free[u] := cur;
  p := a[u];
  while (p <> nil) do
  begin
    v := p^.v;
    if (matchy[v]=0) or ((free[matchy[v]]<>cur) and (find(matchy[v]))) then
    begin
      matchx[u] := v;
      matchy[v] := u;
      exit(true);
    end;
    p := p^.next;
  end;
  exit(false);
end;

procedure disp(p:pnode);
begin
  if (p = nil) then exit;
  disp(p^.next);
  dispose(p);
end;

procedure add(u,v:longint);
var
  p : pnode;
begin
  new(p);
  p^.v := v;
  p^.next := a[u];
  a[u] := p;
end;

function buildGraph : boolean;
var
  i, j : longint;
  flag : boolean;
begin
  for i:=1 to n do
  begin
    disp(a[i]);
    a[i] := nil;
  end;
  for i:=1 to n do
  begin
    flag := false;
    for j:=1 to n do
      if (abs(c[i]-j)*t[i] <= cc) then
      begin
        flag := true;
        add(i,j);
      end;
    if (not flag) then exit(false);
  end;
  exit(true);
end;

function check : boolean;
var
  i, j : longint;
  temp : boolean;
begin
  temp := buildGraph;

  if (not temp) then exit(false);

  fillchar(free,sizeof(free),0);
  fillchar(matchx,sizeof(matchx),0);
  fillchar(matchy,sizeof(matchy),0);
  for i:=1 to n do
  begin
    cur := i;
    if (not find(i)) then exit(false);
  end;
  exit(true);
end;

procedure solve;
var
  low, high, mid : longint;
begin
  low := 0;
  high := maxt;// * n;
  while (low <= high) do
  begin
    mid := (low + high) div 2;
    cc := mid;
    if (check) then
    begin
      res := cc;
      high := mid - 1;
    end
    else
      low := mid + 1;
  end;
end;

var
  i : longint;

BEGIN
  assign(input,fin); reset(input);
    readln(n);
    maxt := 0;
    for i:=1 to n do
    begin
      readln(c[i],t[i]);
      maxt := max(maxt, t[i] * max(c[i]-1,n-c[i]));
//      maxt := max(maxt,t[i]);
    end;
  close(input);

  solve;

  assign(output,fou); rewrite(output);
    writeln(res);
  close(output);
END.