import java.util.*; import java.io.*; public class Main{ static final Reader sc = new Reader(); static final PrintWriter out = new PrintWriter(System.out,false); public static void main(String[] args) throws Exception { long n = sc.nextLong(); long m = sc.nextLong(); long ans = n/1000/m*1000; out.println(ans); out.flush(); sc.close(); out.close(); } static void trace(Object... o) { System.out.println(Arrays.deepToString(o));} } class Reader { private final InputStream in; private final byte[] buf = new byte[1024]; private int ptr = 0; private int buflen = 0; public Reader() { this(System.in);} public Reader(InputStream source) { this.in = source;} private boolean hasNextByte() { if (ptr < buflen) return true; ptr = 0; try{ buflen = in.read(buf); }catch (IOException e) {e.printStackTrace();} if (buflen <= 0) return false; return true; } private int readByte() { if (hasNextByte()) return buf[ptr++]; else return -1;} private boolean isPrintableChar(int c) { return 33 <= c && c <= 126;} private void skip() { while(hasNextByte() && !isPrintableChar(buf[ptr])) ptr++;} public boolean hasNext() {skip(); return hasNextByte();} public String next() { if (!hasNext()) throw new NoSuchElementException(); StringBuilder sb = new StringBuilder(); int b = readByte(); while (isPrintableChar(b)) { sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } public long nextLong() { if (!hasNext()) throw new NoSuchElementException(); boolean minus = false; long num = readByte(); if(num == '-'){ num = 0; minus = true; }else if (num < '0' || '9' < num){ throw new NumberFormatException(); }else{ num -= '0'; } while(true){ int b = readByte(); if('0' <= b && b <= '9') num = num * 10 + (b - '0'); else if(b == -1 || !isPrintableChar(b)) return minus ? -num : num; else throw new NoSuchElementException(); } } public int nextInt() { long num = nextLong(); if (num < Integer.MIN_VALUE || Integer.MAX_VALUE < num) throw new NumberFormatException(); return (int)num; } public double nextDouble() { return Double.parseDouble(next()); } public char nextChar() { if (!hasNext()) throw new NoSuchElementException(); return (char)readByte(); } public String nextLine() { while (hasNextByte() && (buf[ptr] == '\n' || buf[ptr] == '\r')) ptr++; if (!hasNextByte()) throw new NoSuchElementException(); StringBuilder sb = new StringBuilder(); int b = readByte(); while (b != '\n' && b != '\r') { sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } public int[] nextIntArray(int n) { int[] res = new int[n]; for (int i=0; i