#include <bits/stdc++.h>
#ifdef dbg
#define D(...) fprintf(stderr, __VA_ARGS__)
#define DD(...) D("[Debug] "#__VA_ARGS__ " = "), \
              debug_helper::debug(__VA_ARGS__), D("\n")
#include "C:\Users\wsyear\Desktop\OI\templates\debug.hpp"
#else
#define D(...) ((void)0)
#define DD(...) ((void)0)
#endif
#define rep(i, j, k) for (int i = (j); i <= (k); ++i)
#define per(i, j, k) for (int i = (j); i >= (k); --i)
#define SZ(v) int((v).size())
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second
using ll = long long;
using pii = std::pair<int, int>;
using pll = std::pair<ll, ll>;

template<class T> void chkmn(T &x, T y) { if (y < x) x = y; }
template<class T> void chkmx(T &x, T y) { if (y > x) x = y; }

using namespace std;

const int maxn = 1 << 11;

int n, m;
bitset<maxn> a[maxn], b[maxn];

int main() {
  cin.tie(nullptr) -> ios::sync_with_stdio(false);
  cin >> n, m = (1 << n);
  rep (i, 0, m - 1) rep (j, 0, m - 1) {
    int x;
    cin >> x;
    if (x) a[i].set(j);
  }
  per (k, n - 1, 0) {
    rep (i, 0, m - 1) b[i] = a[i], a[i].reset();
    rep (i, 0, m - 1) rep (j, 0, m - 1) {
      int res = 0;
      if (b[i].test(j)) res ^= 1;
      if (b[(i + m - (1 << k)) & (m - 1)].test(j)) res ^= 1;
      if (b[(i + (1 << k)) & (m - 1)].test(j)) res ^= 1;
      if (b[i].test((j + m - (1 << k)) & (m - 1))) res ^= 1;
      if (b[i].test((j + (1 << k)) & (m - 1))) res ^= 1;
      if (res) a[i].set(j);
    }
  }
  int cnt = 0;
  rep (i, 0, m - 1) cnt += a[i].count();
  cout << cnt << '\n';
  rep (i, 0, m - 1) rep (j, 0, m - 1) if (a[i].test(j)) cout << i << " " << j << "\n";
}