def solveans(dat):
    last=dat[0][1]
    ans=L
    for i in range(1,N):
        ans+=abs(last-dat[i][1])
    ans+=dat[i][-1]
    return ans

T=int(input())
for _ in range(T):
    N,L=map(int,input().split())
    datx=[]
    daty=[]
    for i in range(N):
        x,y=map(int,input().split())
        datx.append((x,y,i))
        daty.append((y,x,i))
    datx.sort()
    daty.sort()
    ansx=solveans(datx)
    ansy=solveans(daty)
    print(N)
    if ansx<ansy:
        for x,y,o in datx:
            print(x,y)
    else:
        for x,y,o in daty:
            print(x,y)