from collections import defaultdict

n,m=map(int,input().split())

lst=[[] for i in range(m)]
for i in range(n):
    b,c=map(int,input().split())
    b-=1
    c-=1
    lst[c].append(b)
    
class UnionFind():
    def __init__(self,n):
        self.n=n
        self.parents=[-1]*n
    def find(self,x):
        if self.parents[x]<0:
            return x
        else:
            self.parents[x]=self.find(self.parents[x])
            return self.parents[x]
    def union(self,x,y):
        x=self.find(x)
        y=self.find(y)
        if x==y:
            return
        if self.parents[x]>self.parents[y]:
            x,y=y,x
        self.parents[x]+=self.parents[y]
        self.parents[y]=x
    def size(self,x):
        return -self.parents[self.find(x)]
    def same(self,x,y):
        return self.find(x)==self.find(y)
    def members(self,x):
        rood=self.find(x)
        return [i for i in range(self.n) if self.find(i)==root]
    def roots(self,x):
        return [i for i,x in enumerate(self.parents) if x<0]
    def group_count(self):
        return len(self.roots())
    def all_group_members(self):
        groum_members=defaultdict(list)
        for member in range(self.n):
            group_members[self.find(member)].append(member)
        return group_members
    def __str__(self):
        return '\n'.join(f'{r}: {m}' for r, m in self.all_group_members().items())
    
slime=UnionFind(m)
ans=0
for i in range(m):
    if len(lst[i])<2:
        continue
    for j in range(len(lst[i])):
        for k in range(j+1,len(lst[i])):
            if slime.same(lst[i][j],lst[i][k]):
                continue
            slime.union(lst[i][j],lst[i][k])
            ans+=1
print(ans)