#!/usr/bin/env python
# 579B_member.py - Codeforces.com/problemset/problem/579/B by Sergey 2015

import unittest
import sys

###############################################################################
# Member Class (Main Program)
###############################################################################


class Member:
    """ Member representation """

    def __init__(self, test_inputs=None):
        """ Default constructor """

        it = iter(test_inputs.split("\n")) if test_inputs else None

        def uinput():
            return next(it) if it else sys.stdin.readline().rstrip()

        # Reading single elements
        [self.n] = map(int, uinput().split())

        # Reading a single line of multiple elements
        self.nums = []
        for i in range(self.n*2-1):
            self.nums.append(list(map(int, uinput().split())))

        # Translating into pairs dict
        self.pairs = []
        for i in range(len(self.nums)):
            for j in range(len(self.nums[i])):
                self.pairs.append((self.nums[i][j], i+1, j))

        self.spairs = reversed(sorted(self.pairs))

    def calculate(self):
        """ Main calcualtion function of the class """

        result = [0] * (self.n * 2)

        paired = set()

        for p in self.spairs:
            if p[1] not in paired and p[2] not in paired:
                result[p[1]] = p[2] + 1
                result[p[2]] = p[1] + 1
                paired.add(p[1])
                paired.add(p[2])

        return str(" ".join(map(str, result)))

###############################################################################
# Unit Tests
###############################################################################


class unitTests(unittest.TestCase):

    def test_single_test(self):
        """ Member class testing """

        # Constructor test
        test = "2\n6\n1 2\n3 4 5"
        d = Member(test)
        self.assertEqual(d.n, 2)
        self.assertEqual(d.nums[0], [6])
        self.assertEqual(d.nums[1], [1, 2])

        # Sample test
        self.assertEqual(Member(test).calculate(), "2 1 4 3")

        # Sample test
        test = (
            "3\n487060\n3831 161856\n845957 794650 976977\n" +
            "83847 50566 691206 498447\n" +
            "698377 156232 59015 382455 626960")
        self.assertEqual(Member(test).calculate(), "6 5 4 3 2 1")

        # Sample test
        test = ""
        # self.assertEqual(Member(test).calculate(), "0")

        # My tests
        test = ""
        # self.assertEqual(Member(test).calculate(), "0")

        # Time limit test
        # self.time_limit_test(5000)

    def time_limit_test(self, nmax):
        """ Timelimit testing """
        import random
        import timeit

        # Random inputs
        test = str(nmax) + " " + str(nmax) + "\n"
        numnums = [str(i) + " " + str(i+1) for i in range(nmax)]
        test += "\n".join(numnums) + "\n"
        nums = [random.randint(1, 10000) for i in range(nmax)]
        test += " ".join(map(str, nums)) + "\n"

        # Run the test
        start = timeit.default_timer()
        d = Member(test)
        calc = timeit.default_timer()
        d.calculate()
        stop = timeit.default_timer()
        print("\nTimelimit Test: " +
              "{0:.3f}s (init {1:.3f}s calc {2:.3f}s)".
              format(stop-start, calc-start, stop-calc))

if __name__ == "__main__":

    # Avoiding recursion limitaions
    sys.setrecursionlimit(100000)

    if sys.argv[-1] == "-ut":
        unittest.main(argv=[" "])

    # Print the result string
    sys.stdout.write(Member().calculate())