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Byteotia lies on a peninsula. As far back as from the times of king Bitol
railways have been being the basic means of transport in Byteotia. King Bitol
has a superspeed railway line built. The line connects eastern and western
coasts of the peninsula, runs through all the towns of Byteotia and thus
determines their enumeration: the first town on the line has the number
and the last has
. The town number
lies on
the western coast and the town number
lies on the eastern coast.
Recently, thanks to the minister Byterowicz, the economy of Byteotia has
developed very rapidly and the present-day transport network needs to be quickly
modernised. King Byteol has given orders for many motorways to be constructed
(in the framework of the next -year plan). Each of the motorways
is to join directly two chosen towns of Byteotia. As each motorway is going to
be constructed by a different government agency and on each of the motorways
different vignettes are going to be obligatory, it has been decided that the
motorways must not cross neither one another nor the railway line. Thus the only
solution is to construct each motorway to the north or to the south of the
railway line. Figure 2 shows a sample arrangement of motorways (presented as
dotted arcs, while the railway line is drawn as the solid line).
His Majesty King Byteol has already decided which pairs of towns are to be directly connected by motorways. Your task is to determine which motorways should lie to the north from the railway line, and which to the south. Remember, however, that the motorways must not cross neither one another nor the railway line.
Write a program which:
In the first line of the standard input there are two integers: the number of
towns and the number of the planned motorways
,
. In the following lines there are pairs of
towns which are to be connected by motorways. In the
-st line
there are two integers
,
separated by a single
space: the numbers of the towns that the
-th motorway is to connect,
. Pairs of towns are not repeated in the input
data.
Your program should write to the standard output an arrangement plan of the
motorways or a single word NIE ("no" in Polish), if it is not
possible to construct all the motorways according to the given rules. If the
construction of the motorways is possible then your program should write
lines to the standard output. In the
-th line there
should be one capital letter, respectively: N - if the motorway
connecting the towns
and
should be constructed to
the north of the railway line, or S - if to the south of the railway
line. If there exist many possible solutions, your program should write only one
of them (arbitrary).
For the input data:
8 7 1 2 1 3 2 4 5 7 4 8 7 8 6 8
the correct result is:
N N S S S N N
Task author: Tomasz Walen.