======================== C source ==============================

#include <stdio.h>
#include <stdlib.h>

int a[2048];
int n, m = 0, o;

int c[1024];
int d[1024];

int
funa ()
{
  int i, j;

  for (i = 0, j = 0; i < n; i++)
    j += a[i];

  return j;
}

void
funb (int i)
{
  int j, k;

  if (i > funa ())
    return;

  for (j = 0, k = 1; j < n; j++)
    if (c[j] != d[j])
      k = 0;

  if (k)
    {
      if (i < o)
	o = i;
      return;
    }

  for (j = 0; j < n; j++)
    {
      c[j] = (a[j] + c[j] + 1) % a[j];
      funb (i + 1);
      c[j] = (a[j] + c[j] - 1) % a[j];
      c[j] = (a[j] + c[j] - 1) % a[j];
      funb (i + 1);
      c[j] = (a[j] + c[j] + 1) % a[j];
    }
}

void
funx (int i)
{
  int j;

  if (i == n)
    {
      o = 32767;
      funb (0);
      if (o > m)
	m = o;
    }
  else
    for (j = 0; j < a[i]; j++)
      {
	c[i] = j;
	funx (i + 1);
      }
}

void
funny (int i)
{
  int j;

  if (i == n)
    funx (0);
  else
    for (j = 0; j < a[i]; j++)
      {
	d[i] = j;
	funny (i + 1);
      }
}


int
main ()
{
  int i;

  n = 47;
  for (i = 0; i < n; i++)
    a[i] = i + 1;

  funny (0);
  printf ("%d\n", m);

  return 0;
}


======================== Pascal source ==============================


Const m : Integer = 0;

Var a : Array [0 .. 2047] Of Integer;
    c : Array [0 .. 1023] Of Integer;
    d : Array [0 .. 1023] Of Integer;
    n, o : Integer;

Function funa : Integer;
Var i, j : Integer;
Begin
  j := 0;
  For i := 0 To n - 1 Do
    Inc (j, a[i]);
  funa := j;
End;

Procedure funb (i : Integer);
Var j : Integer;
    k : Boolean;
Begin
  If i > funa Then
    Exit;

  k := True;
  For j := 0 To n - 1 Do
    If c[j] <> d[j] Then
      k := False;

  If k Then
  Begin
    If i < o Then
      o := i;
    Exit;
  End;

  For j := 0 To n - 1 Do
  Begin
    c[j] := (a[j] + c[j] + 1) Mod a[j];
    funb (i + 1);
    c[j] := (a[j] + c[j] - 1) Mod a[j];
    c[j] := (a[j] + c[j] - 1) Mod a[j];
    funb (i + 1);
    c[j] := (a[j] + c[j] + 1) Mod a[j];
  End;
End;

Procedure funx (i : Integer);
Var j : Integer;
Begin
  If i = n Then
  Begin
    o := 32767;
    funb (0);
    If o > m Then
      m := o;
  End Else
  For j := 0 To a[i] - 1 Do
  Begin
    c[i] := j;
    funx (i + 1);
  End;
End;

Procedure funny (i : Integer);
Var j : Integer;
Begin
  If i = n Then
    funx (0)
  Else
  For j := 0 To a[i] - 1 Do
  Begin
    d[i] := j;
    funny (i + 1);
  End;
End;

Var i : Integer;

Begin
  n := 47;
  
  For i := 0 To n - 1 Do
    a[i] := i + 1;

  funny (0);
  WriteLn (m);
End.