def main():
    N = int(raw_input())
    its = []
    for i in xrange(N):
        a, b = map(int,raw_input().split())
        its.append((a,b))
    its.sort()
    ans=en1=en2=0
    for (nst,nen) in its:
        if en1<nst:
            ans+=1
            en1=min(nen,en2)
            en2=max(nen,en2)
        else:    
            if en1>nen:
                en1,nen=nen,en1
            if en2>nen:
                en2=nen
    print ans
 
if __name__=='__main__':
    T=int(raw_input())
    while T>0:
        main()
        T-=1