#include <stdio.h>
#include <stdlib.h>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char *argv[]) {
	int n;
	int data[100][100];
	int i = 0, j = 0;
	int k = 0, l = 0;//K要走的站點數量 l是中間站點 
	int t = 0;
	scanf("%d",&n);
	for (i=1; i<n; i++) {
		for (j=i+1; j<=n; j++) {
			scanf("%d",&data[i][j]);
		}
	}
	for (k=2; k<n; k++) {
		for (i=1; i<=n-k; i++) {
			j = i + k;//起始位置i 終點位置i+k 
			for (l=i+1; l<=j; l++) {
				t = data[i][l] + data[l][j];
				if (t < data[i][j]) {
					data[i][j] = t;
				}
			}
		}
	}
	printf("%d\n",data[1][n]);
	return 0;
}