if __name__ == '__main__':
    volcanoes = []
    for i in range(int(input())):
        input_volcanoe = input().split()
        volcanoes.append([int(input_volcanoe[0]), int(input_volcanoe[1])])
    # print(volcanoes)

    sorted_volcanoes = []
    while len(volcanoes) > 0:
        min_volcano = volcanoes[0]
        index_to_rm = 0
        i = 1
        while i < len(volcanoes):
            if volcanoes[i][0] <= min_volcano[0]:
                if volcanoes[i][0] == min_volcano[0]:
                    # volcanoes[i][1] < min_volcano[1]
                    if len(sorted_volcanoes) != 0 and (not abs(volcanoes[i][1] - sorted_volcanoes[-1][1]) < abs(min_volcano[1] - sorted_volcanoes[-1][1])):
                        break
                min_volcano = volcanoes[i]
                index_to_rm = i
            i += 1
        volcanoes.pop(index_to_rm)
        sorted_volcanoes.append(min_volcano)

    length = 0
    i = 1
    while i < len(sorted_volcanoes):
        length += abs(sorted_volcanoes[i][0] - sorted_volcanoes[i-1][0])
        length += abs(sorted_volcanoes[i][1] - sorted_volcanoes[i-1][1])
        i += 1

    print(length)