import time
import sys

f1=open('in19_4.txt','r')
f2=open('out_24_19_4.txt','w')

row=f1.readline()
lst=row.split(' ')
n=len(lst)
a=[ [0 for col in range(n)] for row in range(n)]
i=0
while row :
    for j in range(len(lst)):
        a[i][j]=int(lst[j])
    row=f1.readline()
    lst=row.split(' ')
    i=i+1

b=[]
f1.close()
for i in range(n):
    cnt=0
    for j in range(n):
        if a[j][i]==0:
           cnt=cnt+1

        if cnt==n:
            b.append(i)
if len(b)==0:
    f2.write("Labelling is not possible")
    f2.close()
else:
    stop=1
    i=0
    while stop :
        x=b[i]
        for j in range(n):
            if a[x][j]==1:
                exist=0
                for k in range(len(b)):
                    if b[k]==j:
                        exist=1
                        break
                if exist==0:
                    b.append(j)
        if i==n-1:
            stop=0
            break
        i=i+1
        
f2.write("Labelling:\n")
for i in range(len(b)):
    f2.write(str(b[i])+" - "+str(i+1)+"\n")
f2.close()