#include <iostream>
#include <vector>
using namespace std;
#define int long long
signed main(){
int n, d; cin >> n >> d;
vector<vector<int>> cons (n);
int u, v;
for (int reader = 0; reader < n - 1; ++reader) {
cin >> u >> v;
u--; v--;
cons[u].push_back(v);
cons[v].push_back(u);
}
vector<int> wins (n), redchild (n);
auto dfswins = [&](auto&& self, int i, int from) -> int{
int red = 0, redi;
for(int c : cons[i]){
if(c == from) continue;
if(self(self, c, i) == 0){
red++;
redi = c;
}
}
if(red == 1) redchild[i] = redi;
return wins[i] = red;
};
dfswins(dfswins, 0, -1);
int redforce = 0;
auto findredforce = [&](auto&& self, int i, int from) -> void {
if(wins[i] == 0){
redforce++;
for(int c : cons[i]){
if(c == from) continue;
self(self, c, i);
}
}
if(wins[i] == 1){
self(self, redchild[i], i);
}
};
findredforce(findredforce, 0, -1);
vector<int> winup (n, -1);
int violet = 0;
auto dfs3 = [&](auto&& self, int i, int from) -> void{
if(from == -1){
winup[i] = false;
if(wins[i] == false) violet++;
}
else if(wins[i] == 0){
if(winup[from] == false && wins[from] == 1) winup[i] = true;
else{
winup[i] = false;
violet++;
}
}
else{
if(winup[from] == false && wins[from] == 0) winup[i] = true;
else winup[i] = false;
}
for(int c : cons[i]){
if(c == from) continue;
self(self, c, i);
}
};
dfs3(dfs3, 0, -1);
if(wins[0] > 0) cout << n*n - violet*redforce;
else cout << violet*redforce;
return 0;
}
