package main

import (
	"fmt"
)

func resolve(N, M int) int {
	return ((N / M) / 1000) * 1000
}

func main() {
	var N int
	var M int

	fmt.Scanf("%d\n", &N)
	fmt.Scanf("%d\n", &M)

	fmt.Println(resolve(N, M))
}