#include<bits/stdc++.h>
using namespace std;
using ll=long long;
/* debugger */
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define dbg(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define dbg(x...)
#endif
/* end of debugger */
int main() {
int n,k;
cin>>n>>k;
vector<vector<int>> e(n);
for(int i=0;i<n-1;i++) {
int u,v;
cin>>u>>v;
e[u-1].push_back(v-1);
e[v-1].push_back(u-1);
}
vector<int> dp(n,0);
auto dfs=[&](int cur,int par,auto &&dfs)->int{
vector<int> cd={-1,-1};
for(int node:e[cur]) {
if(node==par) continue;
cd.push_back(dfs(node,cur,dfs));
}
sort(cd.begin(),cd.end());
return dp[cur]=cd[cd.size()-2]+1;
};
cout<<(dfs(0,-1,dfs)<k?"DA\n":"NE\n");
}
