import sys


def input(): return sys.stdin.readline().rstrip('\n')


sys.setrecursionlimit(10 ** 6)


def main():
    n, k = map(int, input().split())
    if n < k:
        print(-1)
        return
    arr = [[] for _ in range(n)]

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

    z = []

    def dfs(a, p, h):
        z.append(h)
        for b in arr[a]:
            if b != p:
                dfs(b, a, h + 1)

    dfs(0, None, 0)

    z.sort()
    print(sum(z[:k]))


if __name__ == '__main__':
    main()