Project Euler #81: Path sum: two ways

_{This problem is a programming version of Problem 81 from projecteuler.net}

In the matrix below, the minimal path sum from the top left to the bottom right, by only moving to the right and down, is indicated in bold and is equal to .

Find the minimum path sum in given matrix.

Input Format

Each testcase begins with an integer followed by N lines containing the description of the matrix.

Constraints

Output Format

A single line for each testcase containing the value of the minimal path sum.

Sample Input

5
131 673 234 103 18
201 96 342 965 150
630 803 746 422 111
537 699 497 121 956
805 732 524 37 331

Sample Output