n = int(input())
g = [[] for _ in range(n)]
for _ in range(n-1):
    a,b = map(int,input().split())
    g[a-1].append(b-1)
    g[b-1].append(a-1)

leaf = [v for v in range(n) if len(g[v]) == 1]

def dfs(g,s):
    dist = [-1]*n
    dist[s] = 0
    parent = [-1]*n
    q = [s]
    for v in q:
        for c in g[v]:
            if c == parent[v]:
                continue
            parent[c] = v
            dist[c] = dist[v] + 1
            q.append(c)
    d = -1
    for v in leaf:
        if s == v: continue
        elif d == -1:
            d = dist[v]
        elif d != dist[v]:
            print("No")
            exit()
    #print(dist,d)

#print(leaf)

c = 0
for s in leaf:
    dfs(g,s)
    c += 1
    if c > 10: break
print("Yes")