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import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;

class Node {
	int i, j;
	
	public Node(int i, int j) {
		this.i = i;
		this.j = j;
	}

	@Override
	public String toString() {
		return i + "-" + j;
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + i;
		result = prime * result + j;
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Node other = (Node) obj;
		if (i != other.i)
			return false;
		if (j != other.j)
			return false;
		return true;
	}

	
}

public class kug {
	private static final String TEST_FILE = "kug1.in";
	private PrintWriter pw = null;
	private BufferedReader br = null;
	
	private static final Node NODE0 = new Node(0,0);
	private static final List<Node> PATH0 = new ArrayList<Node>();
	static {
		PATH0.add(NODE0);
	}
	
	int N;
	int table[][];
	
	kug(boolean skip) throws FileNotFoundException {
		this.pw = new PrintWriter(System.out);
		this.br = new BufferedReader(new InputStreamReader(System.in), 1 << 16);		
		if (skip)
			return;
		
		File file = new File(TEST_FILE);
		if (file.exists()) {
			br = new BufferedReader(new java.io.FileReader(TEST_FILE));
		} else {
			br = new BufferedReader(new InputStreamReader(System.in), 1 << 16);
		}		
	}
	
	void doit() throws IllegalArgumentException, IOException {
		N = Integer.parseInt(br.readLine());
		
		table = new int[N + 1][];
		//table[0] = new int[] { 0 };
		
		for (int i = 1; i <= N; i++) {
			table[i] = new int[N + 1];
			
			StringTokenizer st = new StringTokenizer(br.readLine());
			for (int j = 1; j <= N + 1 - i; j++) {
				table[i][j] = Integer.parseInt(st.nextToken());
			}
			
			//System.out.println(Arrays.toString(table[i]));
		}
		
		List<List<Node>> koszty = new ArrayList<List<Node>>();
		koszty.add(new ArrayList<Node>());
		koszty.get(0).add(NODE0);
		
		Map<Node, Integer> nodes2costs = new HashMap<Node, Integer>();
		nodes2costs.put(NODE0, 0);
		
		for (int ii = 1; ii <= N; ii++) {
			List<Node> l = new ArrayList<Node>();
			for (int i = 1; i <= N; i++) {
				
				for (int j = 1; j <= N; j++) {
					if (ii >= i && ii <= j) {
						Node key = new Node(i, j);
						l.add(key);
						int koszt = table[ii][j - ii + 1];
						//System.out.println(ii + ", " + j + " koszt: " + koszt);
						
						key = new Node(ii, j);
						nodes2costs.put(key, koszt);
					}
				}
			}
			koszty.add(l);
		}
		koszty.add(PATH0);
		
		
		//System.out.println(nodes2costs);
		
//		for (int i = 0; i <= N + 1; i++) {
//			List<Node> l = koszty.get(i);
//			Node[] s = l.toArray(new Node[] {});
//			System.out.println(i + ": " + Arrays.toString(s));
//		}
		
		Map<List<Node>, Integer> pathsToCosts = new HashMap<List<Node>, Integer>();  
		
		pathsToCosts.put(PATH0 , 0);
		
		for (int i = 1; i <= N; i++) {
			List<Node> l = koszty.get(i);

			Map<List<Node>, Integer> newPathsToCosts = new HashMap<List<Node>, Integer>();  
			
			for (Node node : l) {
				
				internal:
				for (List<Node> nd : pathsToCosts.keySet()) {
//					if (nd.size() != i) {
//						continue internal;
//					}
					
					if (nd.contains(node)) {
						continue internal;
					}
					
					Integer cost = pathsToCosts.get(nd);
					if (cost != null) {
						//int koszt = getCost(node);
						int koszt = nodes2costs.get(node);
						
						newPathsToCosts.put(getPath(nd, node), koszt + cost);
					}
				}
			}
			
			//pathsToCosts.putAll(newPathsToCosts);
			pathsToCosts = newPathsToCosts;
		}
		
		int min = Integer.MAX_VALUE;
		for (List<Node> nd : pathsToCosts.keySet()) {
			//System.out.println(nd + " " + pathsToCosts.get(nd));
//			if (nd.size() != N + 1) {
//				continue;
//			}
			if (pathsToCosts.get(nd) < min) {
				min = pathsToCosts.get(nd);
			}
		}
		
		pw.println(min);
		
//		for (List<Node> nd : pathsToCosts.keySet()) {
//			if (nd.size() != N + 1) {
//				continue;
//			}			
//			if (min == pathsToCosts.get(nd)) {
//				System.out.println(nd + " " + pathsToCosts.get(nd));
//			}
//		}
		
		
		pw.flush();
	}
	
	public static void main(String[] args) throws IllegalArgumentException, IOException {
		new kug(true).doit();
	}
	
//	private int getCost(Node node) {
//		return table[node.i][N - node.j + 1];
//	}	
//	
//	private int getCost(List<Node> nodes) {
//		int sum = 0;
//		for (Node nd : nodes) {
//			sum += table[nd.i][nd.j];
//		}
//		return sum;
//	}
//	
//	private List<Node> getPath(Node nd) {
//		List<Node> path = new ArrayList<Node>();
//		path.add(nd);
//		return path;
//	}
//
//	private List<Node> getPath(Node...nodes) {
//		List<Node> path = new ArrayList<Node>();
//		for (Node nd : nodes) {
//			path.add(nd);
//		}
//		return path;
//	}
	
	private List<Node> getPath(List<Node> nodes, Node nd) {
		List<Node> path = new ArrayList<Node>();
		path.addAll(nodes);
		path.add(nd);
		return path;
	}
	
}