program jlh(input,output);
VAR
k,s,i,j,total:integer;
PROCEDURE move(n:integer;VAR s:integer);
VAR
j,i:integer;
BEGIN
IF (n=1) OR (n=2)
THEN s:=s+1
ELSE BEGIN
FOR i:=1 TO n-2 DO
move(i,s);
s:=s+1;
FOR j:=1 TO n-2 DO
move(j,s)
END
END;
BEGIN
k:=0;
write('input total=');
read(total);
move(total,k);
writeln;
writeln('s=',k)
END.
