*for..do
Program HOC24;
var T: longint;
i,X: integer;
begin
write('Nhap X: '); readln(X);
t:=1;
for i:=1 to X do if i mod 2=0 then t:=t*i;
write('T= ',t);
readln
end.
*while..do
Program HOC24;
var T: longint;
i,X: integer;
begin
write('Nhap X: '); readln(X);
i:=2; t:=1;
while i<=X do
begin
t:=t*i;
i:=i+2;
end;
write('T= ',t);
readln
end.