a=open("output.txt","w")

for i in range(1,num_lines+1): #num_lines are the number of lines in the file
    read=linecache.getline('file.txt',i).rstrip('n') #reads line by line from a text file
    splitted=read.split()   #splits the string "read"

    for k in range(i+1,num_lines+1):
        read1=linecache.getline('just_nodes.txt',k).rstrip('n')
        splitted1=read1.split()

        alpha_temp=abs(float(splitted[1])-float(splitted1[1])) #heavy step

        alpha=round(alpha_temp,3)

        if (alpha==1.000):
            a.write(str(splitted1[0]) +' '+ str(splitted[0]) + "n")
a.close()