n, k = map(int, input().split())
info = [list(map(int, input().split())) for i in range(n-1)]

tree = [[] for i in range(n)]
for i in range(n-1):
    tree[info[i][0]].append(info[i][1])

dp = [[0]*(n+1) for i in range(n)]

#すべて白色で塗る通り数は、それぞれの部分木に対して1通り
for i in range(n):
    dp[i][0] = 1

    
def dfs(pos):
    cnt = 1
    #部分木が葉のとき
    if not tree[pos]:
        dp[pos][cnt] = 1
        return cnt #cnt = 1

    for child_pos in tree[pos]:
        cnt_child = dfs(child_pos)
        tmp = [0]*(n+1)
        for i in range(cnt+1):
            for j in range(cnt_child+1):
                if i+j >= n+1:
                    break
                tmp[i+j] += dp[pos][i]*dp[child_pos][j]
        cnt += cnt_child
        for i in range(cnt+1):
            dp[pos][i] = tmp[i]

    dp[pos][cnt] = 1 
    return cnt
dfs(0)
print(dp[0][k])