var i, n: longint;ans: real;
begin readln(n); ans := 1; for i := 1 to n do ans := ans * i; writeln(ans);end.
var
i, n: longint;ans: real;
begin
readln(n);
ans := 1;
for i := 1 to n do ans := ans * i;
writeln(ans);
end.