#include<bits/stdc++.h>
using namespace std;


int main(void){
  int N;

  cin >> N;

  string s;
  for(int i=0;i<N;i++) s += (char)('A' + i);

  string rs,ls;
  cout << 0 << endl;
  fflush(stdout);
  cin >> rs;
  if(rs == "Vacant")return 0;
  cout << N-1 << endl;
  fflush(stdout);
  cin >> ls;
  if(ls == "Vacant")return 0;

  int l=0,r=N-1;
  while(r-l>1){
      int mid = (r+l)/2;
      cout << mid << endl;
      fflush(stdout);
      string ma;
      cin >> ma;
      if(ma == "Vacant")return 0;
      if(ma == ls && (mid-1-l)%2 != 0){
          rs = ma; r = mid;
      }else if(ma != ls && (mid-1-l)%2 == 0){
          rs = ma; r = mid;
      }else if(ma == rs && (r-mid+1)%2 != 0){
          ls = ma; l = mid;
      }else{
          ls = ma; l = mid;
      }
  }

  return 0;
}

/*
    let ok=0,ng=arr.length; //okが左側にあるとき
    while(Math.abs(ok-ng)>1){
        const mid = Math.floor((ok+ng)/2);
        if(isOK) ok = mid;
        else ng = mid;
    }
*/