N = int(input())

P = [0] * N
Edge = []

for _ in range(N-1):
    v, u = map(int, input().split())
    P[v-1] += 1
    P[u-1] += 1
    Edge.append((v-1, u-1))
    Edge.append((u-1, v-1))
    
S = [k for k, v in enumerate(P) if v == 1]

def getPath(s, i):
    global N, P, S
    D = [float('inf')] * N
    D[s] = 0
    while True:
        update = False
        for f, t in Edge:
            if D[f] != float('inf') and D[t] > D[f] + 1:
                D[t] = D[f] + 1
                update = True
        if not update:
            break
    
    res = -1
    for e in S[i+1:]:
        if res < 0:
            res = D[e]
        elif res != D[e]:
            return -1
    return res

res = -1
for i, s in enumerate(S[:-1]):
    v = getPath(s, i)
    if v < 0:
        print('No')
        break
    elif res < 0:
        res = v
    elif res != v:
        print('No')
        break
else:
    print('Yes')