Do iterative traversal of second tree and find first lead node in it as " temp2"
temp2 = s2 [ 0 ] NEW_LINE s2 . pop ( 0 ) NEW_LINE while ( temp2 and not isLeaf ( temp2 ) ) : NEW_LINE INDENT s2 . insert ( 0 , temp2 . right ) NEW_LINE s2 . insert ( 0 , temp2 . left ) NEW_LINE temp2 = s2 [ 0 ] NEW_LINE s2 . pop ( 0 ) NEW_LINE DEDENT