import numpy as np
from scipy.optimize import linear_sum_assignment

def solve(input_filename, output_filename):
    with open(input_filename, 'r') as file:
        N = int(file.readline().strip())
        distances = [list(map(int, file.readline().split())) for _ in range(N)]

    cost_matrix = np.array(distances)
    row_ind, col_ind = linear_sum_assignment(cost_matrix)

    total_distance = cost_matrix[row_ind, col_ind].sum()

    with open(output_filename, 'w') as output_file:
        output_file.write(str(total_distance))

solve('cc.in', 'cc.out')