Minimum Path Sum in a grid?

int MinPathSum(int[][] grid) {

int m = grid.Length, n = grid[0].Length;

for (int i = 1; i < m; i++) grid[i][0] += grid[i - 1][0];

for (int j = 1; j < n; j++) grid[0][j] += grid[0][j - 1];

for (int i = 1; i < m; i++) {

for (int j = 1; j < n; j++) {

grid[i][j] += Math.Min(grid[i - 1][j], grid[i][j - 1]);

return grid[m - 1][n - 1];