#include <iostream>
#include <vector>
#include <cstring>

using namespace std;

long long gcd(long long a, long long b) { return a ? gcd(b % a, a) : b; }

int A[1010];
bool vis[1010];

int main() {
  int N, K;
  for(cin >> N >> K; N || K; cin >> N >> K) {
    /* Compute the permutation induced by the shuffle. */
    int M = 0;
    for(int i = 0; i < K && i < N; i++) {
      for(int j = (N - i - 1) / K * K + i; j >= 0; j -= K) {
        A[M++] = j;
      }
    }

    /* Compute the lcm of the cycle lengths of the permutation. */
    long long res = 1;
    memset(vis, 0, sizeof(vis));
    for(int i = 0; i < N; i++) {
      int x = i;
      int ln = 0;
      while(!vis[x]) {
        vis[x] = true;
        x = A[x];
        ln++;
      }

      /* Careful to divide then multiply here. */
      if(ln) res = res / gcd(res, ln) * ln;
    }
    cout << res << endl;
  }
}