n = int(input())
g = [[] for _ in range(n)]
vi = [0] * n
for _ in range(n - 1):
    a, b = map(int, input().split())
    vi[a - 1] += 1
    vi[b - 1] += 1
    g[a - 1].append(b - 1)
    g[b - 1].append(a - 1)
s = [0]
d = [-1] * n
d[0] = 0
while s:
    p = s.pop()
    for node in g[p]:
        if d[node] == -1:
            d[node] = d[p] + 1
            s.append(node)
k = d.index(max(d))
s = [k]
d = [-1] * n
d[k] = 0
while s:
    p = s.pop()
    for node in g[p]:
        if d[node] == -1:
            d[node] = d[p] + 1
            s.append(node)
r = max(d)
if r % 2 == 1:
    for i in range(n):
        if vi[i] >= 3:
            print('No')
            break
    else:
        print('Yes')
else:
    c = d.index(r // 2)
    if d.count(c) >= 2:
        print('No')
    else:
        s = [c]
        d = [-1] * n
        d[c] = 0
        while s:
            p = s.pop()
            for node in g[p]:
                if d[node] == -1:
                    d[node] = d[p] + 1
                    s.append(node)
        for i in range(n):
            if (i != c and vi[i] >= 3) or (vi[i] == 1 and d[i] != r // 2):
                print('No')
                break
        else:
            print('Yes')