uses crt;
var n:integer;
gt:real;
{------------------------chuong-trinh-con-tinh-giai-thua-------------------------}
function giaithua(x:integer):real;
var i:integer;
begin
giaithua:=1;
for i:=1 to x do
giaithua:=giaithua*i;
end;
{----------------------chuong-trinh-chinh-------------------------}
begin
clrscr;
write('Nhap n='); readln(n);
gt:=giaithua(n);
writeln(n,'!=',gt:0:0);
readln;
end.