#include<bits/stdc++.h>
#define rep(x,y,z) for(int x=y;x<=z;x++)
#define drep(x,y,z) for(int x=y;x>=z;x--)
#define ull unsigned long long
#define ll long long
using namespace std;
inline int read()
{
	int x=0;bool flag=1;char ch=getchar();
	while(ch<'0'||ch>'9') {if(ch=='-')flag=0;ch=getchar();}
	while(ch>='0'&&ch<='9') {x=(x<<3)+(x<<1)+ch-'0';ch=getchar();}
	if(flag) return x;
	return ~(x-1);
} 
inline void write(int x)
{
	if(x<0) {x=~(x-1);putchar('-');}
	if(x>9) write(x/10);
	putchar(x%10+'0');
}
/////////////////////////
const int N=1e3+50;
int nc;
struct G
{
	int ar;
	int nx;
}a[N<<1];
int aj;
int hd[N];
inline void ADD(int x,int y)
{
	a[++aj].ar=y;
	a[aj].nx=hd[x];
	hd[x]=aj;
}
int b[N][N];
ll ans;
inline void dfs(int x,int cl,int dep)
{
	dep++;
	for(int i=hd[cl];i;i=a[i].nx)
	{
		if(!b[x][a[i].ar])
		{
			b[x][a[i].ar]=1;
//			cout<<ans<<endl;
			ans+=(dep>>1)+(dep&1);
//			cout<<ans<<","<<x<<" "<<a[i].ar<<" "<<dep<<"()"<<(dep>>1)+(dep&1)<<endl;
			dfs(x,a[i].ar,dep);
		}
	}
}
int main()
{
    freopen("Sergeyas.in","r",stdin);
	freopen("Sergeyas.out","w",stdout);
    nc=read();
    int s1,s2;
    rep(i,2,nc)
    {
    	s1=read(),s2=read();
		ADD(s1,s2);
		ADD(s2,s1); 
	}
	rep(i,1,nc) b[i][i]=1,dfs(i,i,0);
	ans>>=1;
	cout<<ans<<endl;
    return 0;
}