2005 minus his half, and then minus the remaining half, until the 2005 one, ask the remaining number

2005 minus his half, and then minus the remaining half, until the 2005 one, ask the remaining number

It's the other third,
If it is, then the formula is 2005 * (1 / 2 * 2 / 3 * 3 / 4 *) 2004 / 2005), which can be continued in brackets, becomes 1 / 2005, so 1 is left
If you cut it by half, it will become 1 / 2, if you cut it by one third, it will become 2 / 3 If you subtract 1 / 2005, it becomes 2004 / 2005)