Problem:
Score : 100 points

Problem Statement

We will buy a product for N yen (the currency of Japan) at a shop.

If we use only 1000-yen bills to pay the price, how much change will we receive?

Assume we use the minimum number of bills required.

Constraints

1 \leq N \leq 10000

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the amount of change as an integer.

Sample Input 1

1900

Sample Output 1

100

We will use two 1000-yen bills to pay the price and receive 100 yen in change.

Sample Input 2

3000

Sample Output 2

0

We can pay the exact price.

Solution in Lua (LuaJIT 2.1.0) (judge verdict: Accepted)

function rl()
   local r = {}
   for word in io.read():gmatch("%S+") do
      table.insert(r, tonumber(word))
   end
   return r
end

function ru()
   return unpack(rl())
end

function pu(x, ...)
   if x then
      io.write(x, ' ')
      return pu(...)
   else
      io.write('\n')
   end
end

N = ru()

pu(math.fmod(1000000 - N, 1000))