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/**
 * @author Tadeusz Faber (SI-Consulting SA).
 * 
 * Potyczki Algorytmiczne 2014.
 * 
 * 2014-05-12 Runda 1A. Kuglarz. 
 *  
 * Pamiec: 128MB.
 * Czas: ?s.
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;

public final class kug {

	private static Reader in = null;

	/**
	 * Zwroc kolejna liczbe calkowita ze strumienia in
	 * 
	 * @return wczytana liczba
	 */
	private static int nextInteger() {

		int r = 0;
		boolean minus = false;
		char c;

		try {
			do {
				c = (char) in.read();
			} while (c == ' ' || c == '\n' || c == '\r');
			if (c == '-') {
				minus = true;
				c = (char) in.read();
			}
			do {
				r = r * 10 + (int) c - 48;
				c = (char) in.read();
			} while (c != ' ' && c != '\n' && c != '\r' && c != (char) -1);
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		if (minus) {
			return -r;
		} else {
			return r;
		}
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) throws IOException {

		in = new BufferedReader(new InputStreamReader(System.in));

		int n = nextInteger(); // 1..2 000
		int[] min1 = new int[n + 1]; // min w kolumnie
		int[] min2 = new int[n + 1]; // druga wartosc min w kolmnie
		int[] prz = new int[n + 1]; // koszt dla jednego kubka (1-1, 2-2, ..)
		for (int i = 1; i <= n; i++) {
			min1[i] = Integer.MAX_VALUE;
			min2[i] = Integer.MAX_VALUE;
		}
		for (int i = 1; i <= n; i++) {
			for (int j = i; j <= n; j++) {
				int x = nextInteger(); // 1..1 000 000 000
				if (i == j) {
					prz[i] = x;
				}
				if (min1[j] > x) {
					min2[j] = min1[j];
					min1[j] = x;
				} else if (min2[j] > x) {
					min2[j] = x;
				}
			}
		}

		int max = min1[1], maxj = 1;
		long r = min1[1];
		for (int j = 2; j <= n; j++) {
			r += min1[j];
			if (max < min1[j]) {
				max = min1[j];
				maxj = j;
			}
		}
		int x = 0; // liczba przedzialow jednoelementowych (1-1, 2-2, ..)
		for (int j = 1; j <= n; j++) {
			if (j != maxj && min1[j] == prz[j]) {
				x += 1;
			}
		}
		int min = Integer.MAX_VALUE;
		for (int j = 1; j <= n; j++) {
			if (x >= 2) {
				if (min > min2[j]) {
					min = min2[j];
				}
			} else {
				// dla x = 0 bedzie problem:(
				if (min > prz[j] && prz[j] >= min2[j]) {
					min = prz[j];
				}
			}
		}
		if (max > min) {
			r = r - max + min;
		}
		System.out.println(r);
	}
}