# c1 oa
```python=
def soln(points):
# assuming no dup points
dd = collections.defaultdict(set)
for x, y in points:
dd[x].add(y)
ans = 0
for x, y in points:
for _x in [x+1, x+2]:
for _y in [y-2, y-1, y, y+1, y+2]:
if _y in dd[_x]:
ans += 1
for _x in [x]: # it's reduced to a 1D problem
for _y in [y+1, y+2]:
if _y in dd[_x]:
ans += 1
return ans
```