#include <bits/stdc++.h>
using namespace std;
int G[100010];
int A[1000];
int g(int q) {
  int n = 2, m, i, g, t, nn;
  memset(A, 0, sizeof(A));
  n = 2;
  nn = -1;
  while (q >= n * (n + 1) / 2) {
    m = q - n * (n + 1) / 2;
    if (m % n != 0) {
      n++;
      continue;
    }
    m /= n;
    t = 0;
    for (i = m + 1; i < m + n + 1; i++) {
      t ^= G[i];
    }
    A[t] = 1;
    if ((t == 0) && (nn == -1)) nn = n;
    n++;
  }
  for (i = 0; i < 1000; i++)
    if (A[i] == 0) break;
  G[q] = i;
  return nn;
}
int main() {
  int i, n, k, j, d;
  memset(G, 0xFF, sizeof(G));
  scanf("%d", &n);
  for (i = 0; i < n; i++) g(i);
  printf("%d\n", g(n));
  return 0;
}
