#include<bits/stdc++.h>

#define rep(i,a,n)     for(int i=a;i<n;i++)
#define rep3(n)        for(int i=0;i<n;i++)
#define ll             long long
#define int            long long
#define pb             push_back
#define all(v)         v.begin(),v.end()
#define endl           "\n"
#define eb             emplace_back
#define x              first
#define y              second
#define gcd(a,b)       __gcd(a,b)
#define mem1(a)        memset(a,-1,sizeof(a))
#define mem0(a)        memset(a,0,sizeof(a))
#define pres(a,x)      a.find(x)!=a.end()
#define sz(a)          (int)a.size()
#define pii            pair<int,int>
#define hell           1000000007
#define elasped_time   1.0 * clock() / CLOCKS_PER_SEC
using namespace std;


template<typename T1,typename T2>istream& operator>>(istream& in,pair<T1,T2> &a){in>>a.x>>a.y;return in;}
template<typename T1,typename T2>ostream& operator<<(ostream& out,pair<T1,T2> a){out<<a.x<<" "<<a.y;return out;}
template<typename T,typename T1>T maxs(T &a,T1 b){if(b>a)a=b;return a;}
template<typename T,typename T1>T mins(T &a,T1 b){if(b<a)a=b;return a;}

const int N=2e5+5;


struct node{
    int a=0;
    node (int val=0){
        a=val;
    }
    void merge(node &n1,node &n2){
        this->a=(n1.a+n2.a);
    }
};
struct update{
  int val=0;
  update(int t=0){
     val=t;
  }
  void combine(update &par,int tl,int tr){
      val+=par.val;
  }
  void apply(node &node,int tr,int tl){
      node.a+=val*(tr-tl+1);
      val=0;
  }
};
template<typename node,typename update>
struct segtree{
  node t[4*N];
  bool lazy[4*N];
  update zaker[4*N];
  int tl[4*N];
  int tr[4*N];
  node nul;
  inline void pushdown(int v){
     if(lazy[v]){    
       apply(zaker[v],v);
       lazy[v]=0;
       zaker[v].apply(t[v],tr[v],tl[v]);
     }
  }
  inline void apply(update &u,int v){
      if(tl[v]!=tr[v]){
          lazy[2*v]=lazy[2*v+1]=1;
          zaker[2*v].combine(u,tl[2*v],tr[2*v]);
          zaker[2*v+1].combine(u,tl[2*v+1],tr[2*v+1]);
      }
  }
  void build(int v,int start,int end){
      tl[v]=start;
      tr[v]=end;
      if(start==end){
          t[v].a=1;
      }
      else{
          int m=(start+end)/2;
          build(2*v,start,m);
          build(2*v+1,m+1,end);
          t[v].merge(t[2*v],t[2*v+1]);
     }
  }
  void zeno(int v,int l,int r,update val){
      pushdown(v);
      if(tr[v]<l || tl[v]>r)return;
      if(l<=tl[v] && tr[v]<=r){
            t[v].a+=val.val*(tr[v]-tl[v]+1);
            apply(val,v); 
            return;
      }
      zeno(2*v,l,r,val);
      zeno(2*v+1,l,r,val);
      t[v].merge(t[2*v],t[2*v+1]);
  }
  node query(int v,int l,int r){
      if(tr[v]<l || tl[v]>r)return nul;
      pushdown(v);
      if(l<=tl[v] && tr[v]<=r){
         return t[v];
      }
      node a=query(2*v,l,r);
      node b=query(2*v+1,l,r);
      node ans;
      ans.merge(a,b);
      return ans;
  }
public:
  node query(int l,int r){
      return query(1,l,r);
  }
  void upd(int l,int r,update val){
      return zeno(1,l,r,val);
  }   
};

segtree<node,update>seg;

int solve(){
 	int n;cin>>n;
 	if(n==1){
 		cout<<1<<endl;return 0;
 	}
 	vector<int>g[N];
 	rep3(n-1){
 		int a,b;
 		cin>>a>>b;
 		g[a].pb(b);
 		g[b].pb(a);
 	}
 	auto deg=[&](int x){
 		return sz(g[x]);
 	};
 	seg.build(1,1,n);
 	for(int i=2;i<=n;i++){
 		update upd;
 		upd.val=deg(i-1)-1;
 		for(auto j: g[i-1]){
 			if(j<i-1)upd.val--;
 		}
 		seg.upd(i,n,upd);
 	}
 	int ans=seg.query(1,n).a;
 	for(int i=n-1;i>0;i--){
 		update upd;
 		upd.val=deg(i+1)-1;
 		for(auto j:g[i+1]){
 			if(j>i+1)upd.val--;
 		}
 		seg.upd(1,n,upd);
 		for(auto j:g[i+1]){
 			update upd;
 			upd.val=-1;
 			if(j+1<i+1){
 				seg.upd(j+1,i,upd);
 			}
 		}
 		ans+=seg.query(1,i).a;
 	}
 	cout<<ans<<endl;
 return 0;
}
signed main(){
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    #ifdef SIEVE
    sieve();
    #endif
    #ifdef NCR
    init();
    #endif
    int t=1;//cin>>t;
    while(t--){
        solve();
    }
    return 0;
}
 

Measured memory_bytes: 36984