//#pragma GCC optimize("Ofast,no-stack-protector")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
//#pragma GCC optimize("Ofast,fast-math")
//#pragma GCC target("avx,avx2")
//#pragma GCC optimize(2)
//#pragma GCC optimize(3)
//#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
// #define int long long
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef double db;
#define F(i, a, b) for(int i = a; i <= (b); ++i)
#define F2(i, a, b) for(int i = a; i < (b); ++i)
#define dF(i, a, b) for(int i = a; i >= (b); --i)
template<typename T> void debug(string s, T x) {
	cerr << "[" << s << "] = [" << x << "]\n";
}
template<typename T, typename... Args> void debug(string s, T x, Args... args) {
	for (int i = 0, b = 0; i < (int)s.size(); i++) if (s[i] == '(' || s[i] == '{') b++;
	else if (s[i] == ')' || s[i] == '}') b--;
	else if (s[i] == ',' && b == 0) {
		cerr << "[" << s.substr(0, i) << "] = [" << x << "] | ";
		debug(s.substr(s.find_first_not_of(' ', i + 1)), args...);
		break;
	}
}
#ifdef ONLINE_JUDGE
#define Debug(...)
#else
#define Debug(...) debug(#__VA_ARGS__, __VA_ARGS__)
#endif
#define pb push_back
#define fi first
#define se second
#define Mry fprintf(stderr, "%.3lf MB\n", (&Med - &Mbe) / 1048576.0)
#define Try cerr << 1e3 * clock() / CLOCKS_PER_SEC << " ms\n";
typedef long long ll;
// namespace Fread {const int SIZE = 1 << 19; char buf[SIZE], *S, *T; inline char getchar() {if (S == T) {T = (S = buf) + fread(buf, 1, SIZE, stdin); if (S == T) return '\n';} return *S++;}}
// namespace Fwrite {const int SIZE = 1 << 19; char buf[SIZE], *S = buf, *T = buf + SIZE; inline void flush() {fwrite(buf, 1, S - buf, stdout), S = buf;} inline void putchar(char c) {*S++ = c;if (S == T) flush();} struct NTR {~NTR() {flush();}} ztr;}
// #ifdef ONLINE_JUDGE
// #define getchar Fread::getchar
// #define putchar Fwrite::putchar
// #endif
inline int ri() {
	int x = 0;
	char c = getchar();
	while (c < '0' || c > '9') c = getchar();
	while (c >= '0' && c <= '9') x = (x << 3) + (x << 1) + (c ^ 48), c = getchar();
	return x;
}
inline void wi(int x) {
	if (x < 0) {
		putchar('-'), x = -x;
	}
	if (x > 9) wi(x / 10);
	putchar(x % 10 + 48);
}
inline void wi(int x, char s) {
	wi(x), putchar(s);
}
bool Mbe;
// mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
const int mod = 998244353;
const int inf = 0x3f3f3f3f;
const ll infll = 0x3f3f3f3f3f3f3f3f;
const int _ = 4200 + 5;

int n;

bool a[_][_];

bitset<_> b[_];

vector<bool> Gauss(int n, int m) {
	F(i, 1, n) {
		int cur = i;
		while(cur <= m && !b[cur].test(i)) cur++;
		if(cur > m) {
			cur = i;
//			Debug("1kri");
//			return vector<bool>(n + 1, 0);
		}
		if(cur != i) swap(b[cur], b[i]);
		F(j, 1, m) if(i != j && b[j].test(i)) b[j] ^= b[i];
	}
	vector<bool> res(n + 1, 0);
	F(i, 1, n) res[i] = b[i].test(0);
	return res;
}

int Id[_ * _];

pii Id2[_ * _];

bool c[_][_], c1[_][_], a1[_][_];

pii fx(int x, int y, int Fx) {
	if(Fx == 1) {
		if(x == 1) x = n;
		return {x, y};
	} else if(Fx == 2) {
		if(x == n) x = 1;
		return {x, y};
	} else if(Fx == 3) {
		if(y == 1) y = n;
		return {x, y};
	} else {
		if(y == n) y = 1;
		return {x, y};
	}
}

namespace part1 {
	void solve() {
		int t = 0;
		F(i, 1, n) F(j, 1, n) Id[(i - 1) * n + j] = ++t, Id2[t] = {i, j};
		F(i, 1, t) {
			b[i][0] = a[Id2[i].fi][Id2[i].se];
			int x = Id2[i].fi, y = Id2[i].se;
			b[i][(x - 1) * n + y] = 1;
			x = Id2[i].fi == 1 ? n : Id2[i].fi - 1;
			b[i][(x - 1) * n + y] = 1;
			x = Id2[i].fi == n ? 1 : Id2[i].fi + 1;
			b[i][(x - 1) * n + y] = 1;
			y = Id2[i].se == 1 ? n : Id2[i].se - 1;
			b[i][(x - 1) * n + y] = 1;
			y = Id2[i].se == n ? 1 : Id2[i].se + 1;
			b[i][(x - 1) * n + y] = 1;
		}
		vector<bool> ans = Gauss(t, t);
		int s = 0;
		F(i, 1, t) if(ans[i]) {
			s += ans[i];
		}
		cout << s << '\n';
		F(i, 1, t) if(ans[i]) {
			cout << Id2[i].fi - 1 << ' ' << Id2[i].se - 1 << '\n';
			c[Id2[i].fi][Id2[i].se] = 1;
		}
		F(i, 1, n) {
			F(j, 1, n) cerr << c[i][j] << ' ';
			cerr << '\n';
		}
	}
}

bitset<_> C[_][2];

//inline int pre(int x) {
//	if(x == 1) return n;
//	return x - 1;
//}
//inline int nxt(int x) {
//	if(x == n) return 1;
//	return x + 1;
//}

bool Med;
signed main() {
//	 Mry;
//	freopen("1.txt", "r", stdin);
//	freopen("2.txt", "w", stdout);
	auto pre = [&](int x) {
		return x == 1 ? n : x - 1;
	};
	auto nxt = [&](int x) {
		return x == n ? 1 : x + 1;
	};
	n = (1 << ri());
	F(i, 1, n) F(j, 1, n) a[i][j] = ri();
//	if(n <= 16) return part1::solve(), 0;
	int t = 0;
	F(j, 1, 2) F(i, 1, n) Id[(i - 1) * n + j] = ++t;//, Id2[t] = {i, j};
	F(j, 1, 2) F(i, 1, n) C[i][j & 1][Id[(i - 1) * n + j]] = 1;
	F(j, 3, n) F(i, 1, n) {
		C[i][j & 1] ^= C[i][pre(j) & 1] ^ C[pre(i)][pre(j) & 1] ^ C[nxt(i)][pre(j) & 1];
		C[i][j & 1][0] = (C[i][j & 1][0] ^ a[i][pre(j)]);
	}
//	Try;
	F(j, n, n) F(i, 1, n) {
		b[i] = C[i][j & 1] ^ C[pre(i)][j & 1] ^ C[nxt(i)][j & 1] ^ C[i][pre(j) & 1];
		b[i].flip(Id[(i - 1) * n + nxt(j)]);
		b[i][0] = (b[i][0] ^ a[i][j]);
	}
	F(j, 1, 1) F(i, 1, n) {
		b[i + n] = C[i][pre(j) & 1];
		b[i + n].flip(Id[(i - 1) * n + j]);
		b[i + n].flip(Id[(pre(i) - 1) * n + j]);
		b[i + n].flip(Id[(nxt(i) - 1) * n + j]);
		b[i + n].flip(Id[(i - 1) * n + nxt(j)]);
		b[i + n][0] = (b[i + n][0] ^ a[i][j]);
	}
	vector<bool> ans = Gauss(n + n, t);
	F(i, 1, n) if(ans[i]) c[i][1] = 1;
	F(i, n + 1, n + n) if(ans[i]) c[i - n][2] = 1;
//	F(i, 1, t) if(ans[i]) {
//		c[Id2[i].fi][Id2[i].se] = 1;
//	}
	F(j, 3, n) F(i, 1, n) c[i][j] = a[i][pre(j)] ^ c[i][pre(j)] ^ c[i][pre(pre(j))] ^ c[pre(i)][pre(j)] ^ c[nxt(i)][pre(j)];
	int s = 0;
	F(i, 1, n) F(j, 1, n) if(c[i][j]) s++;
	cout << s << '\n';
	F(i, 1, n) F(j, 1, n) {
		if(c[i][j]) cout << i - 1 << ' ' << j - 1 << '\n';
	}
	//
	F(i, 1, n) {
		F(j, 1, n) cerr << c[i][j] << ' ';
		cerr << '\n';
	}
	F(i, 1, n) F(j, 1, n) if(c[i][j]) {
		c1[i][j] ^= 1;
		c1[pre(i)][j] ^= 1;
		c1[nxt(i)][j] ^= 1;
		c1[i][pre(j)] ^= 1;
		c1[i][nxt(j)] ^= 1;
	}
	bool flg = 1;
	F(i, 1, n) F(j, 1, n) flg &= (c1[i][j] == a[i][j]);
	Debug(flg);
//	F(i, 1, n) {
//		F(j, 1, n) cerr << c1[i][j] << ' ';
//		cerr << '\n';
//	}
	//
	// Try;
	return 0;
}

/*
2
0 0 0 0
0 0 0 0
0 1 0 0
0 0 0 0

3
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 1 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0

4
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
*/