import sys
sys.setrecursionlimit(10 ** 6)

N, K = list(map(int, input().split()))
ab = []
for i in range(N-1):
    a, b = list(map(int, input().split()))
    ab.append([a-1, b-1])

if N < K:
    print(-1)
    exit()

G = []
for i in range(N):
    G.append([False] * N)

for a, b in ab:
    G[a][b] = True
    G[b][a] = True

# for i in range(N):
#     print(G[i])

VISITED = [None] * N

DEPTH = [None] * N

def dfs(p, d):
    VISITED[p] = True
    DEPTH[p] = d

    # if all(VISITED):
    #     return

    for i, b in enumerate(G[p]):
        if b and not VISITED[i]:
            dfs(i, d + 1)

dfs(0, 0)

# print(':', VISITED)
# print(':', DEPTH)

DEPTH.sort()
ans = sum(DEPTH[:K])
print(ans)