#include<bits/stdc++.h>
using namespace std;
int n;
int a[201][201];
int dp[201];
int main()
{
	cin >> n;
	for (int i = 1; i < n; i++)
	{
		for (int j = i + 1; i <= n; i++)
		{
			cin >> a[i][j];
		}
		dp[i] = 1000000;
		// 这里的初始化好像没有执行
	} 
	for (int i = n - 1; i >= 1; i--)
	{
		for (int j = i + 1; j <= n; j++)
		{
			dp[i] = min(dp[i], dp[j] + a[i][j]);
		}
	}
	cout << dp[n] << endl;
  	return 0;
}