import java.io.BufferedInputStream;

import java.util.Arrays;

import java.util.Scanner;

public class Solution {

final static int N = 511;

static int match[] = new int[N];

static boolean st[] = new boolean [N];

static boolean g[][] = new boolean [N][N];

static int a[][] = new int [N][N];

static int n;

boolean DFS (int x) {

int i, t;

for (i = 1; i <= n; ++i) if (!st[i] && g[i][x]) {

t = match[i];

match[i] = x;

st[i] = true;

if (t == 0 || DFS (t)) return true;

match[i] = t;

}

return false;

}

boolean chk (int x) {

int i, j, k;

for (i = 1; i <= n; ++i)

for (j = 1; j <= n; ++j)

g[i][j] = a[i][j] <= x ? true : false;

int ans = 0; Arrays.fill (match, 0);

for (i = 1; i <= n; ++i) {

Arrays.fill (st, false);

if (DFS (i)) ans++;

}

return ans == n;

}

void sgu218 () {

Scanner in = new Scanner (new BufferedInputStream (System.in));

int c[] = new int [N*N];

int i, j, k;

n = in.nextInt();

k = 0;

for (i = 1; i <= n; ++i)

for (j = 1; j <= n; ++j) {

a[i][j] = in.nextInt();

c[k] = a[i][j];

k++;

}

Arrays.sort (c, 0, k);

int low = 0, up = k - 1;

while (up > low) {

int mid = (low + up) / 2;

if (chk (c[mid]))

up = mid;

else

low = mid + 1;

}

chk (c[up]);

System.out.println(c[up]);

for (i = 1; i <= n; ++i)

System.out.printf ("%d %d\n", i, match[i]);

}

public static void main(String[] args) {

Solution sguSolver = new Solution ();

sguSolver.sgu218 ();

}

}