# import sys
# sys.setrecursionlimit(100000)

N = int(input())
COR = [tuple((map(int, input().split()))) for _ in range(N)]


class Group:
    
    def __init__(self):
        self.n = 0
        self.x = []
        self.y = []
        
#     def insertx(self, x):
#         self.x[x] = None

#     def inserty(self, y):
#         self.y[y] = None
        
    def new_cor_n(self):
        if self.n == 0:
            return 0
        return len(self.x) * len(self.y) - self.n

    def join(self, group):
        self.n += group.n
        for x in group.x:
            self.x[x] = None
        for y in group.y:
            self.y[y] = None
        group.n = 0

def grouping_y(group, y, xcor, ycor):
    ycor[y][1] = True
    group.y.append(y)
    for x in ycor[y][0]:
        if xcor[x][1]:
            continue
        group.n += 1
        grouping_x(group, x, xcor, ycor)
        
def grouping_x(group, x, xcor, ycor):
    xcor[x][1] = True
    group.x.append(x)
    for y in xcor[x][0]:
        if ycor[y][1]:
            continue
        group.n += 1
        grouping_y(group, y, xcor, ycor)
    
if N <= 2:
    print(0)
else:
    xcor, ycor = {}, {}
    for xi, yi in COR:
        if xi in xcor:
            xcor[xi][0].append(yi)
        else:
            xcor[xi] = [[yi], False]
        if yi in ycor:
            ycor[yi][0].append(xi)
        else:
            ycor[yi] = [[xi], False]
    group_list = []
    xcor = sorted(xcor.items())
    for x, v in xcor.items():
        if v[1]:
            continue
        group = Group()
        group_list.append(group)
        grouping_x(group, x, xcor, ycor)
    s = 0
    for group in group_list:
        s += group.new_cor_n()
    print(s)

### FIXED CODE ###

# import sys
# sys.setrecursionlimit(20000)


N = int(input())
COR = [tuple((map(int, input().split()))) for _ in range(N)]


class Group:
    
    def __init__(self):
        self.n = 0
        self.x = 0
        self.y = 0
        self.xy = {}
        
    def new_cor_n(self):
        return self.x * self.y - self.n
        

def grouping(group, x, xcor, ycor):
    x_list = []
    group.x += 1
    for y in xcor[x][0]:
        if (x, y) not in group.xy:
            group.n += 1
            group.xy[(x, y)] = None
        if ycor[y][1]:
            continue
        ycor[y][1] = True
        group.y += 1
        for x_ in ycor[y][0]:
            if (x_, y) not in group.xy:
                group.n += 1
                group.xy[(x_, y)] = None
            if xcor[x_][1]:
                continue
            xcor[x_][1] = True
            x_list.append(x_)
    return x_list

if N <= 2:
    print(0)
else:
    xcor, ycor = {}, {}
    for xi, yi in COR:
        if xi in xcor:
            xcor[xi][0].append(yi)
        else:
            xcor[xi] = [[yi], False]
        if yi in ycor:
            ycor[yi][0].append(xi)
        else:
            ycor[yi] = [[xi], False]
    group_list = []
    for i, v in xcor.items():
        if v[1]:
            continue
        group = Group()
        group_list.append(group)
        xcor[i][1] = True
        x_list = [i]
        while True:
            new_x_list = []
            for x in x_list:
                new_x_list += grouping(group, x, xcor, ycor)
            if new_x_list == []:
                break
            x_list = new_x_list
    s = 0
    for group in group_list:
        s += group.new_cor_n()
    print(s)