#include <bits/stdc++.h>
#include <cassert>
using namespace std;
mt19937 timmy_loves_gambling(73);
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define readv(v) do { for(auto &i: v) cin >> i; } while(0)
#define _ << " " <<
#define lf "\n"
#define ll long long
#define ull unsigned long long
#define pii pair<int, int>
#define pll pair<long long, long long>
#define fi first
#define se second
template<typename... Args>
using vec = vector<Args...>;
#ifndef MARCO
bool dbg = 0;
#define infor(str, ...)
#define infof(str, ...)
#else
bool dbg = 1;
#define infor(str, ...) do { print(stderr, str, ##__VA_ARGS__); } while(0)
#define infof(str, ...) do { println(stderr, str, ##__VA_ARGS__); } while(0)
#endif
int N, M;
vec<vec<int>> G;
constexpr int K = 3;
constexpr int mod = 998244353;
vec<ll> P = {4358345, 3509843, 5498345};
signed main() {
ios::sync_with_stdio(0);
cin.tie(0), cout.tie(0);
cin >> N >> M;
G.resize(N);
for(int i = 0; i < N-1; i++) {
int a, b; cin >> a >> b;
a--, b--;
G[a].push_back(b);
G[b].push_back(a);
}
vec<array<ll, K>> st;
vec<array<ll, K>> hash(N, {1, 3, 123589});
vec<int> color(N), f(N), tried(N);
vec<int> sz(N, 1), pt(N, 1);
auto coloring = [&](int v, int from, auto &&self) -> void {
for(auto &u: G[v]) {
if(u == from) continue;
self(u, v, self);
sz[v] += sz[u];
pt[v] += pt[u]+sz[u];
for(int i=0; i<K; i++) {
hash[v][i] = (hash[v][i] + hash[u][i]*P[i]%mod)%mod;
}
}
st.push_back(hash[v]);
};
coloring(0, -1, coloring);
sort(all(st));
st.resize(unique(all(st)) - st.begin());
for(int i = 0; i < N; i++) {
color[i] = lower_bound(all(st), hash[i]) - st.begin();
f[color[i]]++;
}
int ans = 0;
bool ok;
auto proc = [&](int v, int from, int d, int K, auto &&self) -> void {
f[color[v]] += K*d;
if(f[color[v]] < 0) ok = 0;
for(auto &u: G[v]) {
if(u == from) continue;
self(u, v, d+1, K, self);
}
};
auto dfs = [&](int v, int from, auto &&self) -> void {
if(N-pt[v] == M && tried[color[v]] == 0) {
ok = 1;
proc(v, from, 1, -1, proc);
if(ok) ans++;
proc(v, from, 1, +1, proc);
tried[color[v]] = 1;
}
for(auto &u: G[v]) {
if(u == from) continue;
self(u, v, self);
}
};
dfs(0, -1, dfs);
cout << ans << lf;
}
