import java.io.IOException; import java.io.InputStream; import java.util.NoSuchElementException; public class Main { static FastScanner sc = new FastScanner(); public static void main(String[] args) { int N = sc.nextInt(); int i = 1; while(i <= N) { int cnt = 0; cnt += (N+1) / (i*2) * i; cnt += Math.max((N+1) % (i*2) - i, 0); if(cnt%2 == 1) { System.out.println("O"); return; } i *= 2; } System.out.println("X"); } static class FastScanner { private final InputStream in = System.in; private final byte[] buffer = new byte[1024]; private int ptr = 0; private int buflen = 0; private boolean hasNextByte() { if(ptr < buflen) { return true; } else { ptr = 0; try { buflen = in.read(buffer); } catch(IOException e) { e.printStackTrace(); } if(buflen <= 0) { return false; } } return true; } private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;} private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;} private void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;} public boolean hasNext() { skipUnprintable(); 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() { return Long.parseLong(next()); } public int nextInt(){ return Integer.parseInt(next()); } public double nextDouble(){ return Double.parseDouble(next()); } } }