Program zadanie1;
var n:integer;
rn:int64;
{------------------------}
function f(arg:integer):int64;
var fi:integer;
begin
f:=1;
for fi:=1 to arg do begin
f:=f*fi
end
end;
{------------------------}
begin
readln(n);
rn:=f(n);
writeln(rn);
readln
end.