from collections import deque
MOD = 998244353

N = int(input())

degrees = [0]*N
connect = [[] for _ in range(N)]
for _ in range(N-1):
  u,v = map(lambda x:int(x)-1,input().split())
  connect[u].append(v)
  connect[v].append(u)
  degrees[u] += 1
  degrees[v] += 1


q = deque([0])
visited = [False]*N
visited[0] = True
dist = [0]*N
while q:
  v = q.popleft()
  for u in connect[v]:
    if not visited[u]:
      q.append(u)
      visited[u] = True
      dist[u] = dist[v] + 1
  
a = max(range(N),key=lambda x:dist[x])


q = deque([a])
visited = [False]*N
visited[a] = True
dist = [0]*N
while q:
  v = q.popleft()
  for u in connect[v]:
    if not visited[u]:
      q.append(u)
      visited[u] = True
      dist[u] = dist[v] + 1

b = max(range(N),key=lambda x:dist[x])

d = dist[b]
v = b
path = [b]
while d >= 0:
  for u in connect[v]:
    if dist[u] == d-1:
      path.append(u)
      d -= 1
      v = u
      break
  else:
    break

q = deque(path)
visited = [False]*N
for i in path:
  visited[i] = True
dist = [0]*N
while q:
  v = q.popleft()
  for u in connect[v]:
    if not visited[u]:
      q.append(u)
      visited[u] = True
      dist[u] = dist[v] + 1

#print(dist)
c = max(range(N),key=lambda x:dist[x] if x != a and x != b else -1)

#print(a,b,c)

S = set(path)
q = deque([c])
visited = [False]*N
visited[c] = True
dist = [0]*N
while q:
  v = q.popleft()
  if v in S:
    F = v
    q = deque([])
    break
  for u in connect[v]:
    if not visited[u]:
      q.append(u)
      visited[u] = True
      dist[u] = dist[v] + 1

#print(F)

q = deque([F])
visited = [False]*N
visited[F] = True
dist = [0]*N
while q:
  v = q.popleft()
  for u in connect[v]:
    if not visited[u]:
      q.append(u)
      visited[u] = True
      dist[u] = dist[v] + 1

x,y,z = dist[a],dist[b],dist[c]
K = x+y+z
#print(x,y,z)

ans = pow(2,N+2,MOD) - pow(2,N-K,MOD) * (pow(2,x+1,MOD) + pow(2,y+1,MOD) + pow(2,z+1,MOD) - 3)
ans %= MOD

print(ans)