import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


int N;

int Ask(int k) {
  if (k == 0) return 0;
  if (k == N) return N / 2;
  writefln("? %s", k);
  stdout.flush;
  const s = readInt;
  if (s == -1) {
    import core.stdc.stdlib;
    exit(0);
  }
  return s;
}

void Answer(int l, int r) {
  writefln("! %s %s", l + 1, r);
  stdout.flush;
}


int calc(int l, int r) {
  const res = Ask(r) - Ask(l);
  return (r - l) - 2 * res;
}

void main() {
  N = readInt;
  
  const half = calc(0, N / 2);
  if (half == 0) {
    Answer(0, N / 2);
    return;
  }
  int lo = 0, hi = N;
  for (; lo + 1 < hi; ) {
    const mid = (lo + hi) / 2;
    const l = mid / 2, r = N / 2 + (mid + 1) / 2;
    const res = calc(l, r);
    debug {
      writeln(l, " ", r, ": ", res);
    }
    if (res == 0) {
      Answer(l, r);
      return;
    }
    (((half < 0) == (res < 0)) ? lo : hi) = mid;
  }
  assert(false);
}