import os, sys
import math
n = int(input())
r = []
for i in range(n-1):
    r.append(list(map(int, input().split())))
dp = [[0]*n for _ in range(n)]
dp[0][0] = r[0][0]
for i in range(1, n):
    dp[i][i] = r[i - 1][i]
for k in range(1, n):
    for i in range(n - k):
        j = i + k
        dp[i][j] = math.inf
        for m in range(i, j):
            dp[i][j] = min(dp[i][j], dp[i][m] + dp[m+1][j] + r[i][j])
print(dp[0][n - 1])