n=int(input())
ax,ay=map(int,input().split())
bx,by=map(int,input().split())
cx,cy=map(int,input().split())
dx,dy=-1,-1
for i in range(1,n+1):
  if (ax<i and bx<i<cx)or(cx<i<ax and i<bx):
    dx=i
    break
  if (ay<i and by<i<cy)or(cy<i<ay and i<by):
    dy=i
    break
print(n)
if dx>-1:
  print(n)
  for i in range(n):
    print(dx,i+1)
else:
  for i in range(n):
    print(i+1,dy)