n=int(input())
e=[[] for i in range(n)]
for i in range(n-1):
  u,v=map(int,input().split())
  u-=1
  v-=1
  e[u]+=[v]
  e[v]+=[u]
v=[0]*n
u1=[0]*n
q=[0]
while len(q)>0:
  s=q[-1]
  if v[s]==0:
    v[s]=1
    for t in e[s]:
      if v[t]==0:
        q+=[t]
  else:
    for t in e[s]:
      if v[t]==0:
        u1[s]=max(u1[s],u1[t]+1)
    v[s]=0
    q.pop()
ans=0
u2=[0]*n
q=[0]
while len(q)>0:
  s=q[-1]
  if v[s]==0:
    v[s]=1
    u3=sorted([u1[t]+1 for t in e[s] if v[t]==0]+[u2[s]]+[0,0])[-2:]
    u3=u3[::-1]
    for t in e[s]:
      if v[t]==0:
        q+=[t]
        u2[t]=u3[u3[0]==u1[t]+1]+1
  else:
    u4=sorted([u1[t]+1 for t in e[s] if v[t]==0]+[u2[s]])
    for i in range(len(u4)):
      ans=max(ans,u4[i]*(len(u4)-i)+1)
    v[s]=0
    q.pop()
print(ans)