#include <bits/stdc++.h>   #pragma GCC optimize( O3 )   using namespace std;   const long double EPS = 0.000000001;   const long long INF64 = 1000000000000000000;   const long long INF32 = 2000000000;   bool iss_pt_in_triangle(pair<long long, long long> a,                           pair<long long, long long> b,                           pair<long long, long long> c,                           pair<long long, long long> point) {     long long x1 = a.first, x2 = b.first, x3 = c.first, x0 = point.first;     long long y1 = a.second, y2 = b.second, y3 = c.second, y0 = point.second;     long long aa = (x1 - x0) * (y2 - y1) - (x2 - x1) * (y1 - y0);     long long bb = (x2 - x0) * (y3 - y2) - (x3 - x2) * (y2 - y0);     long long cc = (x3 - x0) * (y1 - y3) - (x1 - x3) * (y3 - y0);     if (aa == 0 || bb == 0 || cc == 0) return 1;     if (aa >= 0 && bb >= 0 && cc >= 0) return 1;     if (aa <= 0 && bb <= 0 && cc <= 0) return 1;     return 0;   }   bool iss_ll(long long &__1, long long &__2) { return INF64 / __1 >= __2; }   bool equal(long double _1, long double _2) { return (abs(_1 - _2) < EPS); }   bool iss_sqr(long long &__1) {     long long __2 = sqrt((long double)__1);     return __2 * __2 == __1;   };   bool iss_prime(long long __1) {     for (long long i = 2; i * i <= __1; ++i)       if (!(__1 % i)) return 0;     return 1;   }   long long gcd(long long __1, long long __2) {     while (__1 && __2)       if (__1 > __2)         __1 = __1 % __2;       else         __2 = __2 % __1;     return __1 + __2;   }   long long lcm(long long &__1, long long &__2) {     return __1 * __2 / (gcd(__1, __2));   }   long long sq_cube(long long x) {     if (x == 0) return 1;     long long l = 0, r = 2e6;     while (l + 1 < r) {       long long m = (l + r) / 2;       if (m * m * m > x)         r = m;       else         l = m;     }     return l;   }   set<long long> G[100100];   vector<long long> GR[100100];   bool used[100100];   void dfs(long long v) {     if (used[v]) return;     used[v] = 1;     for (long long i : G[v]) dfs(i);   }   long long n, k;   long long step(long long k) {     long long res = 1;     for (long long i = 0; i < k; ++i) res *= 3;     return res;   }   long long dfss(long long v, long long deep) {     long long ans = deep;     used[v] = 1;     if (deep != k) {       if ((GR[v].size() < 4 && deep > 0 && deep != k) ||           (deep == 0 && GR[v].size() < 3)) {         cout <<  No               <<   n ;         exit(0);       }     }     for (long long i : GR[v]) {       if (used[i]) continue;       ans = max(dfss(i, deep + 1), ans);     }     if (ans != k) {       cout <<  No             <<   n ;       exit(0);     }     return ans;   }   signed main(signed argc, const char *argv[]) {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     cin >> n >> k;     if (k > 20) {       cout <<  No             <<   n ;       return 0;     }     for (long long i = 1; i < n; ++i) {       long long x, y;       cin >> x >> y;       G[x].insert(y);       G[y].insert(x);       GR[x].push_back(y);       GR[y].push_back(x);     }     dfs(1);     for (long long i = 1; i <= n; ++i) {       if (!used[i]) {         cout <<  No               <<   n ;         return 0;       }     }     vector<long long> VEC;     long long k1 = k;     long long pos = 0;     for (long long i = 1; i <= n; ++i)       if (G[i].size() == 1) VEC.push_back(i);     while (k--) {       if (VEC.size() == 0) {         cout <<  No               <<   n ;         return 0;       }       if (k == 0) {         pos = *G[VEC.front()].begin();       }       for (long long i : VEC) {         G[*G[i].begin()].erase(i);         G[i].clear();       }       VEC.clear();       for (long long i = 1; i <= n; ++i) {         if (G[i].size() == 1) VEC.push_back(i);         if (G[i].size() == 2) {           cout <<  No                 <<   n ;           return 0;         }       }     }     memset(used, 0, sizeof(used));     k = k1;     dfss(pos, 0);     cout <<  Yes           <<   n ;   }