```
var island, neigh int
for i := 0; i < len(grid); i++ {
for j := 0; j < len(grid[i]); j++ {
if grid[i][j] == 1 {
island++
if i < len(grid)-1 && grid[i+1][j] == 1 {
neigh++
}
if j < len(grid[i])-1 && grid[i][j+1] == 1 {
neigh++
}
}
}
}
return island*4 - neigh*2
```