#agc036d. [agc036_d]Negative Cycle

[agc036_d]Negative Cycle

Problem Statement

We have a weighted directed graph with NN vertices numbered 00 to N1N-1.

The graph initially has N1N-1 edges. The ii-th edge (0leqileqN20 \\leq i \\leq N-2) is directed from Vertex ii to Vertex i+1i+1 and has a weight of 00.

Snuke will now add a new edge (ij)(i → j) for every pair i,ji, j (0leqi,jleqN1,ineqj0 \\leq i,j \\leq N-1,\\ i \\neq j). The weight of the edge will be \-1\-1 if i<ji < j, and 11 otherwise.

Ringo is a boy. A negative cycle (a cycle whose total weight is negative) in a graph makes him sad. He will delete some of the edges added by Snuke so that the graph will no longer contain a negative cycle. The cost of deleting the edge (ij)(i → j) is Ai,jA_{i,j}. He cannot delete edges that have been present from the beginning.

Find the minimum total cost required to achieve Ringo's objective.

Constraints

  • 3leqNleq5003 \\leq N \\leq 500
  • 1leqAi,jleq1091 \\leq A_{i,j} \\leq 10^9
  • All values in input are integers.

Input

Input is given from Standard Input in the following format:

NN A0,1A_{0,1} A0,2A_{0,2} A0,3A_{0,3} cdots\\cdots A0,N1A_{0,N-1} A1,0A_{1,0} A1,2A_{1,2} A1,3A_{1,3} cdots\\cdots A1,N1A_{1,N-1} A2,0A_{2,0} A2,1A_{2,1} A2,3A_{2,3} cdots\\cdots A2,N1A_{2,N-1} vdots\\vdots AN1,0A_{N-1,0} AN1,1A_{N-1,1} AN1,2A_{N-1,2} cdots\\cdots AN1,N2A_{N-1,N-2}

Output

Print the minimum total cost required to achieve Ringo's objective.


Sample Input 1

3
2 1
1 4
3 3

Sample Output 1

2

If we delete the edge (01)(0 → 1) added by Snuke, the graph will no longer contain a negative cycle. The cost will be 22 in this case, which is the minimum possible.


Sample Input 2

4
1 1 1
1 1 1
1 1 1
1 1 1

Sample Output 2

2

If we delete the edges (12)(1 → 2) and (30)(3 → 0) added by Snuke, the graph will no longer contain a negative cycle. The cost will be 1+1=21+1=2 in this case, which is the minimum possible.


Sample Input 3

10
190587 2038070 142162180 88207341 215145790 38 2 5 20
32047998 21426 4177178 52 734621629 2596 102224223 5 1864
41 481241221 1518272 51 772 146 8805349 3243297 449
918151 126080576 5186563 46354 6646 491776 5750138 2897 161
3656 7551068 2919714 43035419 495 3408 26 3317 2698
455357 3 12 1857 5459 7870 4123856 2402 258
3 25700 16191 102120 971821039 52375 40449 20548149 16186673
2 16 130300357 18 6574485 29175 179 1693 2681
99 833 131 2 414045824 57357 56 302669472 95
8408 7 1266941 60620177 129747 41382505 38966 187 5151064

Sample Output 3

2280211