Nikifor has decided to present the dean of the Department of Mathematics and Mechanics with a linearly independent vector system (you know, that we've just celebrated jubilees of the University and of the Department). A store sells m items of n-dimensional vectors, m <= 2000, 3 <= n <= m. For each vector its price ci is known, 0 < i <= m. Nikifor wants to buy n linearly independent vectors paying for them minimal sum of money. Write a program that would determine which vectors Nikifor should buy or would inform that it is impossible to satisfy his requirements.