#include <bits/stdc++.h>
using namespace std;
long long n, k;
char s[10];
int main() {
  srand(time(0));
  scanf("%lld%lld", &n, &k);
  long long l = 1, r = n;
  while (1) {
    if (r - l <= (long long)4 * k) {
      long long x = rand() % (r - l + 1) + l;
      printf("%lld %lld\n", x, x);
      fflush(stdout);
      scanf("%s", s);
      if (s[0] == 'Y' || s[0] == 'B')
        return 0;
      else {
        l = max(1ll, l - k);
        r = min(n, r + k);
      }
    } else {
      long long mid = (l + r) / 2;
      printf("%lld %lld\n", l, mid);
      fflush(stdout);
      scanf("%s", s);
      if (s[0] == 'B')
        return 0;
      else if (s[0] == 'Y') {
        l = max(1ll, l - k);
        r = min(n, mid + k);
      } else {
        l = max(1ll, mid + 1 - k);
        r = min(n, r + k);
      }
    }
  }
  return 0;
}
