N = int(input())
G = [[] for i in range(N)]
indegree = [0] * N
for _ in range(N - 1):
    a,b = map(int,input().split())
    G[a - 1].append(b - 1)
    G[b - 1].append(a - 1)
    indegree[a - 1] += 1
    indegree[b - 1] += 1
    
more_indeg = 0
for v in range(N):
    if indegree[v] > 2:
        more_indeg += 1
    
# 次数1のある点から、他の全ての点への距離が同じであればOK
# を二回やって成功すればOK
start = -1
start1 = -1
for v in range(N):
    if indegree[v] == 1 and start != -1:
        start1 = v
        break
    if indegree[v] == 1:
        start = v

def check(x):
    stack = []
    dist = [-1] * N
    stack.append([start, 0])
    while stack:
        v, d = stack.pop()
        if dist[v] != -1:
            continue
        dist[v] = d
        for child in G[v]:
            if dist[child] != -1:
                continue
            stack.append([child, d + 1])
        
    ds = set()
    for v in range(N):
        if v == start:
            continue
        if indegree[v] == 1:
            ds.add(dist[v])
            
    return len(ds) == 1

if more_indeg < 2 and check(start) and check(start1):
    print("Yes")
else:
    print("No")