#include<bits/stdc++.h>
#include<atcoder/all>
#define all(a) begin(a),end(a)
#define fin(...) rr vo(pp(__VA_ARGS__))
#define ep(...) emplace(__VA_ARGS__)
#define eb(...) emplace_back(__VA_ARGS__)
#define ef(...) else if(__VA_ARGS__)
#define wh(...) while(__VA_ARGS__)
#define ov4(a,b,c,d,e,...) e
#define fo1(b) for(ll ii=0,bb=(ll)(b);ii<bb;++ii)
#define fo2(i,b) for(ll i=0,bb=(ll)(b);i<bb;++i)
#define fo3(i,a,b) for(ll i=(ll)(a),bb=(ll)(b);i<bb;++i)
#define fo4(i,a,b,c) for(ll i=(ll)(a),bb=(ll)(b),cc=(ll)(c);i<bb;i+=cc)
#define fo(...) ov4(__VA_ARGS__,fo4,fo3,fo2,fo1)(__VA_ARGS__)
#define of2(i,a) for(ll i=(ll)(a)-1;i>=0;--i)
#define of3(i,a,b) for(ll i=(ll)(a)-1,bb=(ll)(b);i>=bb;--i)
#define of4(i,a,b,c) for(ll i=(ll)(a)-1,bb=(ll)(b),cc=(ll)(c);i>=bb;i-=cc)
#define of(...) ov4(__VA_ARGS__,of4,of3,of2)(__VA_ARGS__)
#define fe2(v,a) for(auto&&a:v)
#define fe3(v,...) for(auto&&[__VA_ARGS__]:v)
#define fe(v,...) ov4(__VA_ARGS__,fe3,fe3,fe3,fe2)(v,__VA_ARGS__)
#define RD(T,...) T __VA_ARGS__;li(__VA_ARGS__)
#define LL(...) RD(ll,__VA_ARGS__)
#define UL(n,...) u1 __VA_ARGS__;set_size({n},__VA_ARGS__);li(__VA_ARGS__)
#define UV(n,...) u1 __VA_ARGS__;set_size({n},__VA_ARGS__);vi(__VA_ARGS__)
#define U2(n,m,...) u2 __VA_ARGS__;set_size({n,m},__VA_ARGS__);li(__VA_ARGS__)
#define I(...) template<__VA_ARGS__>
#define J typename
#define O operator
#define rr return
#define uu using
#define cs const
namespace atcoder{}namespace my{void main();void solve();}int main(){my::main();}
namespace my{uu namespace std;uu namespace atcoder;uu is=istream;uu os=ostream;uu vo=void;uu bo=bool;uu dd=long double;
uu ll=long long;uu i64=ll;uu i128=__int128_t;uu ul=unsigned long long;uu u64=ul;uu u128=__uint128_t;
I(J T)uu v1=vector<T>;I(J T)uu v2=v1<v1<T>>;uu u1=v1<ll>;uu u2=v2<ll>;uu str=string;uu strs=v1<str>;str sp=" ",nc="",nl="\n";
uu ml=modint1000000007;is&O>>(is&i,ml&x){ll t;i>>t;x=t;rr i;}os&O<<(os&o,cs ml&x){rr o<<x.val();}uu m1=v1<ml>;uu m2=v2<ml>;

I(J A,J B=A)struct cp{
  A a;B b;cp():a(),b(){}cp(A a,B b):a(a),b(b){}cp(pair<A,B>p):a(p.first),b(p.second){}cp O-()cs{rr cp(-a,-b);}
  cp&O+=(cs cp&c){a+=c.a,b+=c.b;rr*this;}cp O+(cs cp&c)cs{rr cp{*this}+=c;}bo O==(cs cp&c)cs{rr a==c.a&&b==c.b;}
  cp&O-=(cs cp&c){a-=c.a,b-=c.b;rr*this;}cp O-(cs cp&c)cs{rr cp{*this}-=c;}bo O!=(cs cp&c)cs{rr a!=c.a||b!=c.b;}
  bo O<(cs cp&c)cs{rr a!=c.a?a<c.a:b<c.b;}bo O>=(cs cp&c)cs{rr!(*this<c);}friend is&O>>(is&i,cp&c){rr i>>c.a>>c.b;}
  bo O>(cs cp&c)cs{rr a!=c.a?a>c.a:b>c.b;}bo O<=(cs cp&c)cs{rr!(*this>c);}friend os&O<<(os&o,cs cp&c){rr o<<c.a<<sp<<c.b;}
};uu cl=cp<ll>;uu cls=v1<cl>;
I(J T)uu qmax=priority_queue<T>;I(J T)uu qmin=priority_queue<T,v1<T>,greater<T>>;uu dl=deque<ll>;I(J T)uu uset=unordered_set<T>;
I(J T)struct mset:multiset<T>{uu multiset<T>::multiset;vo erase(cs T&x){if(this->count(x))multiset<T>::erase(this->find(x));}};
I(J T,J U)uu umap=unordered_map<T,U>;uu mp=map<ll,ll>;uu ump=umap<ll,ll>;uu sl=set<ll>;uu usl=uset<ll>;uu msl=mset<ll>;
ll oo=3e18;dd ee=1e-12,pi=acosl(-1);u1 dx{-1,0,1,0,-1,1,1,-1},dy{0,-1,0,1,-1,-1,1,1};
ul rnd(){static ul x=76,y=53,z=20,w=41;ul t=(x^(x<<11));x=y,y=z,z=w;rr(w=(w^(w>>19))^(t^(t>>8)));}
ll rnd_rng(ll r){rr rnd()%r;}ll rnd_rng(ll l,ll r){rr rnd()%(r-l)+l;}str Yes(bo y=1){rr y?"Yes":"No";}str No(){rr Yes(0);}

bo odd(ll x){rr x&1;}bo eve(ll x){rr~x&1;}ll pm1(ll x){rr 1-2*(x&1);}ll pw2(ll n){rr 1LL<<n;}
ll rng1(ll l,ll r){rr pw2(r)-pw2(l);}ll rng_bit(ll x,ll l,ll r){rr rng1(l,r)&x;}ll msb(ll x){rr x?63-__builtin_clzll(x):-1;}
ll ppc(ll x,ll l=0,ll r=63){rr __builtin_popcountll(rng_bit(x,l,r));}ll lsb(ll x){rr x?__builtin_ctzll(x):-1;}
ll sqr(ll x){ll r=max(sqrtl(x)-1,dd());wh(r+1<=x/(r+1))++r;rr r;}I(J T)T sq(cs T&a){rr a*a;}I(J T)T cb(cs T&a){rr a*a*a;}
ll l2(u128 x){x|=1;ll r=0;wh(x)x>>=1,++r;rr r;}ll l10(u128 x){x|=1;ll r=0;wh(x)x/=10,++r;rr r;}
u1 io(ll n,ll x=0){u1 a(n);fo(i,n)a[i]=i+x;rr a;}I(J T,J U,J V)bo in(T l,U m,V r){rr l<=m&&m<r;}
I(J T)ll len(cs T&a){rr a.size();}I(J T)bo mu(cs T&a){rr !len(a);}I(J T)auto zt(v1<T>a){fo(i,1,len(a))a[i]+=a[i-1];rr a;}
I(J T)bo at(T x,ll i){rr x>>i&1;}I(J T)T at(cs v1<T>&v,ll i){ll n=len(v);rr v[(i%n+n)%n];}
I(J T)T flo(T x,T y){rr(y<0?flo(-x,-y):(x>=0?x/y:(x+1)/y-1));}I(J T)ll sgn(cs T&a){rr(a>ee)-(a<-ee);}
I(J T)T cei(T x,T y){rr(y<0?cei(-x,-y):(x<=0?x/y:(x-1)/y+1));}I(J T,J U)ll sgn(cs T&a,cs U&b){rr sgn(a-b);}

I(J T)auto&srt(v1<T>&a){sort(all(a));rr a;}I(J T)auto&rv(v1<T>&a){reverse(all(a));rr a;}
I(J T)auto&rsr(v1<T>&a){srt(a),rv(a);rr a;}I(J T)auto&uq(v1<T>&a){srt(a),a.erase(unique(all(a)),end(a));rr a;}
I(J T)T rect(cs v1<T>&s,ll l,ll r){assert(0<=l&&l<=r&&r<=len(s));T t{};if(r)t+=s[r-1];if(l)t-=s[l-1];rr t;}
I(J T)decltype(auto)bg(T&a){rr*begin(a);}I(J T,J U=T)vo af(v1<T>&v,U e={}){v.ep(begin(v),e);}
I(J T)decltype(auto)rb(T&a){rr*rbegin(a);}I(J T)vo df(v1<T>&v){v.erase(begin(v));}
I(J T)T pop(v1<T>&v){T r=rb(v);v.pop_back();rr r;}I(J T)auto slice(cs v1<T>&a,ll l,ll r){rr v1<T>(begin(a)+l,begin(a)+r);}
I(J T)T pop(qmax<T>&q){T r=q.top();q.pop();rr r;}I(J T)T pof(deque<T>&q){T r=bg(q);q.pop_front();rr r;}
I(J T)T pop(qmin<T>&q){T r=q.top();q.pop();rr r;}I(J T)T pob(deque<T>&q){T r=rb(q);q.pop_back();rr r;}
I(J T)auto&O++(v1<T>&v,int){fe(v,e)++e;rr v;}I(J T)auto&O^=(v1<T>&v,cs v1<T>u){copy(all(u),back_inserter(v));rr v;}
I(J T)auto&O--(v1<T>&v,int){fe(v,e)--e;rr v;}I(J T)auto O^(v1<T>v,cs v1<T>&u){rr v^=u;}
I(J T,J U)bo amax(T&a,cs U&b){rr a<b?a=b,1:0;}I(J T,J U)ll lbs(cs v1<T>&a,cs U&b){rr lower_bound(all(a),b)-begin(a);}
I(J T,J U)bo amin(T&a,cs U&b){rr a>b?a=b,1:0;}I(J T,J U)ll ubs(cs v1<T>&a,cs U&b){rr upper_bound(all(a),b)-begin(a);}
I(J T)T max(cs v1<T>&a){rr*max_element(all(a));}I(J T)T sum(cs v1<T>&a){rr accumulate(all(a),T{});}
I(J T)T min(cs v1<T>&a){rr*min_element(all(a));}I(J F,J...A)vo swl(cs F&f,A&...a){(vo)initializer_list<ll>{(vo(f(a)),0)...};}
I(J T=ll,ll n)auto make_vec(u1&s,cs T&x){ll m=pop(s);if constexpr(n==1)rr vector(m,x);else rr vector(m,make_vec<T,n-1>(s,x));}
I(J T=ll,ll n)auto make_vec(cs ll(&t)[n],cs T&x={}){u1 s(n);fo(i,n)s[i]=t[n-i-1];rr make_vec<T,n>(s,x);}
I(J T=ll,ll n,J...A)vo set_size(cs ll(&t)[n],A&...a){swl([&](auto&a){a=make_vec(t,T());},a...);}

struct fio{fio(){cin.tie(0);ios::sync_with_stdio(0);cout<<fixed<<setprecision(12);}}fio;
os&O<<(os&o,u128 x){if(x<10)rr o<<char(x+'0');rr o<<x/10<<char(x%10+'0');}
os&O<<(os&o,i128 x){if(x<0)x=-x,o<<'-';rr o<<u128(x);}I(J T,J U)os&O<<(os&o,cs pair<T,U>&p){rr o<<p.first<<sp<<p.second;}
I(J T)os&O<<(os&o,qmax<T>q){wh(len(q))o<<pop(q)<<sp;rr o;}I(J T)os&O<<(os&o,cs set<T>&v){fe(v,e)o<<e<<(&e==&rb(v)?nc:sp);rr o;}
I(J T)os&O<<(os&o,qmin<T>q){wh(len(q))o<<pop(q)<<sp;rr o;}I(J T)os&O<<(os&o,cs mset<T>&v){fe(v,e)o<<e<<(&e==&rb(v)?nc:sp);rr o;}
I(J T)os&O<<(os&o,cs v1<T>&v){fe(v,e)o<<e<<(&e==&rb(v)?nc:sp);rr o;}I(J T,J U)os&O<<(os&o,cs map<T,U>&m){fe(m,e)o<<e<<nl;rr o;}
I(J T)os&O<<(os&o,cs v2<T>&v){fe(v,e)o<<e<<(&e==&rb(v)?nc:nl);rr o;}I(J T)is&O>>(is&i,v1<T>&v){fe(v,e)i>>e;rr i;}
I(J T)ll pp(cs T&a){cout<<a<<nl;rr 0;}I(J...A)ll li(A&...a){(cin>>...>>a);rr 0;}I(J...A)vo vi(ll i,A&...a){(cin>>...>>a[i]);}
I(J T,J...A)ll pp(cs T&a,cs A&...b){cout<<a;((cout<<sp<<b),...);rr pp(nc);}I(J T,J...A)vo vi(v1<T>&a,A&...b){fo(i,len(a))vi(i,a,b...);}

struct edg{ll t,w;edg(){}edg(ll t,ll w=1):t(t),w(w){}};uu graph=v2<edg>;
u2 tou(cs graph&g){ll n=len(g);u2 a(n);fo(u,n)fe(g[u],v,w)a[u].eb(v);rr a;}
graph tog(cs u2&a){ll n=len(a);graph g(n);fo(u,n)fe(a[u],v)g[u].eb(v);rr g;}
auto ygi(u2&g,ll m){UV(m,a,b);a--,b--;fo(i,m)g[a[i]].eb(b[i]);rr tuple(a,b);}
auto mgi(u2&g,ll m){auto[a,b]=ygi(g,m);fo(i,m)g[b[i]].eb(a[i]);rr tuple(a,b);}auto ti(u2&g){rr mgi(g,len(g)-1);}

u1 en(cs str&s,cs str&b="a"){ll n=len(s);u1 r(n,-1);fo(i,n)if(len(b)==1)r[i]=s[i]-b[0];else fo(j,len(b))if(s[i]==b[j])r[i]=j;rr r;}
str de(cs u1&a,cs str&b="a"){ll n=len(a);str r(n,'|');fo(i,n)if(len(b)==1)r[i]=a[i]+b[0];else fo(j,len(b))if(a[i]==j)r[i]=b[j];rr r;}
u2 en(cs strs&s,cs str&b="a"){u2 r;fe(s,e)r.eb(en(e,b));rr r;}
strs de(cs u2&a,cs str&b="a"){ll n=len(a);strs r(n);fo(i,n)r[i]=de(a[i],b);rr r;}
str ins(){str s;li(s);rr s;}strs inss(ll n){strs s(n);li(s);rr s;}u1 abc(){rr en(ins());}u2 abcs(ll n){rr en(inss(n));}

I(J F)struct rec:F{rec(F&&f):F(forward<F>(f)){}I(J...A)decltype(auto)O()(A&&...a)cs{rr F::O()(*this,std::forward<A>(a)...);}};
I(J...A)u1 zp(A&...a){u1 v;fe({a...},e)v^=e;uq(v);swl([&](u1&a){fe(a,e)e=lbs(v,e);},a...);rr v;}
I(J F,J...A)u1 vs(cs F&f,A&...a){ll n;fe({a...},e)n=len(e);u1 o=io(n);sort(all(o),f);swl([&](u1&a){u1 c=a;fo(i,n)a[i]=c[o[i]];},a...);rr o;}
I(J F)ll bsl(cs F&f,ll o,ll n){wh(abs(o-n)>1)(f((o+n)/2)?o:n)=(o+n)/2;rr o;}
I(J F)dd bsd(cs F&f,dd o,dd n){fo(l2(abs(o-n)/ee))(f((o+n)/2)?o:n)=(o+n)/2;rr o;}
cls rle(cs u1&a){cls r;fe(a,e)len(r)&&e==rb(r).a?++rb(r).b,0:(r.eb(e,1),0);rr r;}cls rce(u1 a){rr rle(srt(a));}
i128 pow(i128 x,u128 n,i128 m=0){i128 r=1;wh(n){if(n&1)r*=x;x*=x;if(m)r%=m,x%=m;n>>=1;}rr r;}
u1 divs(ll n){u1 r;for(ll i=1;i*i<=n;i++)if(n%i==0)r.eb(i),r.eb(n/i);rr uq(r);}
cls fact(ll n){ump m;for(ll i=2;i*i<=n;i++)wh(n%i==0)++m[i],n/=i;if(n>1)++m[n];cls r;fe(m,e)r.eb(e);rr srt(r);}

tuple<u1,u1,u1>dfs_order(cs u2&g,ll s=0){
  ll n=len(g);
  u1 ord,dep(n),par(n);
  v1<tuple<ll,ll,ll>>st{{s,-1,0}};
  wh(len(st)){
    auto[u,p,d]=pop(st);
    ord.eb(u),dep[u]=d,par[u]=p;
    fe(g[u],v)if(v!=p)st.eb(v,u,d+1);
  }
  rr{ord,dep,par};
}

vo main(){ll T=1;fo(T)solve();}
vo solve(){
  LL(N,K);
  u2 g(N);
  fo(N-1){
    LL(a,b);
    g[a].eb(b),g[b].eb(a);
  }
  
  auto[ord,dep,par]=dfs_order(g);
  rv(ord);
  
  m2 dp(N);
  fe(ord,u){
    dp[u].resize(2);//初期化分だけを確保
    dp[u][0]=1,dp[u][1]=1;
    fe(g[u],v)if(v!=par[u]){
      ll n=len(dp[u]),m=len(dp[v]);
      m1 nx(n+m-1);
      
      fo(j,n){
        fo(p,m){
          if(j==n-1&&p<m-1)continue;
          nx[j+p]+=dp[u][j]*dp[v][p];
        }
      }
      swap(dp[u],nx);
    }
  }
  pp(dp[0][K]);
}}