# Original solution
# coding: utf-8
# Your code here!

class UnionFind:
    def __init__(self, n,xy):
        self.parent = list(range(n))#親ノード
        self.size = [1]*n #グループの要素数
        self.xval = [{x} for x,y in xy]
        self.yval = [{y} for x,y in xy]

    def root(self, x): #root(x): xの根ノードを返す．
        while self.parent[x] != x:
            x, self.parent[x] = self.parent[x], self.parent[self.parent[x]]
        return x 
 
    def merge(self, x, y): #merge(x,y): xのいるグループと$y$のいるグループをまとめる
        x, y = self.root(x), self.root(y)
        if x == y:
            return False
        if self.size[x] < self.size[y]: 
            self.size[y] += self.size[x] #yの要素数を更新
            self.parent[x] = y #xをyにつなぐ
            self.xval[y].update(self.xval[x])
            self.yval[y].update(self.yval[x])
        else:
            self.size[x] += self.size[y] #xの要素数を更新
            self.parent[y] = x #yをxにつなぐ
            self.xval[x].update(self.xval[y])
            self.yval[x].update(self.yval[y])
        return True
 
    def issame(self, x, y): #same(x,y): xとyが同じグループにあるならTrue
        return self.root(x) == self.root(y)
        
    def size(self,x): #size(x): xのいるグループの要素数を返す
        return self.size[self.root(x)]

n = int(eval(input()))
xy = [[int(i) for i in input().split()] for j in range(n)] 

UF = UnionFind(n,xy)

xval = dict()
yval = dict()
for i,(x,y) in enumerate(xy):
    if y in yval:
        UF.merge(i,yval[y])
    else:
        yval[y] = i

    if x in xval:
        UF.merge(i,xval[x])
    else:
        xval[x] = i

ans = -n
for i,pi in enumerate(UF.parent):
    if i==pi:
        ans += len(UF.xval[pi]) * len(UF.yval[pi])

#print(xval,yval)

print(ans)






# Optimized solution
# coding: utf-8
# Your code here!

class UnionFind:
    def __init__(self, n):
        self.parent = list(range(n))#親ノード
        self.size = [1]*n #グループの要素数

    def root(self, x): #root(x): xの根ノードを返す．
        while self.parent[x] != x:
            x, self.parent[x] = self.parent[x], self.parent[self.parent[x]]
        return x 
 
    def merge(self, x, y): #merge(x,y): xのいるグループと$y$のいるグループをまとめる
        x, y = self.root(x), self.root(y)
        if x == y:
            return False
        if self.size[x] < self.size[y]: 
            self.size[y] += self.size[x] #yの要素数を更新
            self.parent[x] = y #xをyにつなぐ
        else:
            self.size[x] += self.size[y] #xの要素数を更新
            self.parent[y] = x #yをxにつなぐ
        return True
 
    def issame(self, x, y): #same(x,y): xとyが同じグループにあるならTrue
        return self.root(x) == self.root(y)
        
    def size(self,x): #size(x): xのいるグループの要素数を返す
        return self.size[self.root(x)]

n = int(eval(input()))
xy = [[int(i) for i in input().split()] for j in range(n)] 

UF = UnionFind(n)

xval = dict()
yval = dict()
for i,(x,y) in enumerate(xy):
    if y in yval:
        UF.merge(i,yval[y])
    else:
        yval[y] = i

    if x in xval:
        UF.merge(i,xval[x])
    else:
        xval[x] = i


xcon = dict()
ycon = dict()
for i in range(n):
    pi = UF.root(i)
    x,y = xy[i]
    if pi in xcon:
        xcon[pi].add(x)
    else:
        xcon[pi] = {x}

    if pi in ycon:
        ycon[pi].add(y)
    else:
        ycon[pi] = {y}
        

ans = -n
#print(xcon,ycon)
for key, val in list(xcon.items()):
    ans += len(val) * len(ycon[key])

#print(UF.parent)
#print(xval,yval)

print(ans)