#include<stdio.h>
#include<stdlib.h>
#include<stdint.h>
#include<inttypes.h>

typedef int32_t i32;

#define ALLOC(size,type) ((type*)calloc((size),sizeof(type)))

i32 query (i32 x, i32 y) {
  printf ("? %" PRIi32 " %" PRIi32 "\n", x, y);
  fflush (stdout);
  i32 ans;
  scanf ("%" SCNi32, &ans);
  return ans;
}

void run (void) {
  i32 n;
  scanf ("%" SCNi32, &n);
  i32 size = 1;
  while (size < n) size *= 2;
  i32 *s = ALLOC (2 * size, i32);
  for (i32 i = 0; i < n; ++i) {
    s[i + size] = i + 1;
  }
  for (i32 i = size - 1; i >= 1; --i) {
    if (s[2 * i] == 0) continue;
    if (s[2 * i + 1] == 0) {
      s[i] = s[2 * i];
    } else {
      s[i] = query (s[2 * i], s[2 * i + 1]);
    }
  }
  i32 winner = s[1];
  i32 second = s[2] + s[3] - winner;
  for (i32 i = 2; i < size; ++i) {
    if (s[i] != winner) continue;
    if (s[2 * i] != 0 && s[2 * i + 1] != 0) {
      second = query (second, s[2 * i] + s[2 * i + 1] - winner);
    }
  }
  printf ("! %" PRIi32 "\n", second);
}

int main (void) {
  run();
  return 0;
}