CF1060E

#include<bits/stdc++.h>

using namespace std;

#define gc c=getchar()
#define r(x) read(x)
#define ll long long

template<typename T>
inline void read(T&x){
    x=0;T k=1;char gc;
    while(!isdigit(c)){if(c=='-')k=-1;gc;}
    while(isdigit(c)){x=x*10+c-'0';gc;}x*=k;
}

const int N=2e5+7;

int n;
ll ans=0;
int siz[N];
int cnt[2];
vector<int>G[N];

void dfs(int x,int f,bool d){
    ++cnt[d];
    siz[x]=1;
    for(int i=0;i<G[x].size();++i){
        int v=G[x][i];
        if(v==f)continue;
        dfs(v,x,d^1);
        siz[x]+=siz[v];
    }
    ans+=(ll)siz[x]*(n-siz[x]);
}

int main(){
    // freopen(".in","r",stdin);
    // freopen(".out","w",stdout);
    r(n);
    for(int i=1;i<n;++i){
        int u,v;r(u),r(v);
        G[u].push_back(v);
        G[v].push_back(u);
    }
    dfs(1,0,1);
    ans+=(ll)cnt[0]*cnt[1];
    ans>>=1;
    printf("%lld\n",ans);
    return 0;
}