Simply, count the sea to land transitions .. while looping the array ..

```
public int IslandPerimeter(int[,] grid) {
int perim = 0;
int w = grid.GetLength(0);
int l = grid.GetLength(1);
for(int i=0; i < w; i++)
{
for(int j=0; j < l; j++)
{
if(grid[i,j] == 1)
{
if(i == 0 || grid[i-1, j] == 0){perim++;}
if(i == w-1 || grid[i+1, j] == 0){perim++;}
if(j == 0 || grid[i,j-1] == 0){perim++;}
if(j == l-1 || grid[i,j+1] == 0) {perim++;}
}
}
}
return perim;
}
}
```