public static void Solve()
{
var N = Scanner.Scan <int>();
var P = Scanner.ScanEnumerable <int>().ToArray();
var Q = Scanner.ScanEnumerable <int>().ToArray();
long F(IEnumerable <int> items)
{
var array = items.ToArray();
var list = items.ToList();
list.Sort();
var ret = 0L;
for (var i = 0; i < array.Length; i++)
{
var value = array[i];
ret += Enumeration.Fractorial(array.Length - i - 1) * list.IndexOf(value);
list.Remove(value);
}
return(ret);
}
Console.WriteLine(Math.Abs(F(P) - F(Q)));
}
public static void Solve()
{
var(N, M) = Scanner.Scan <int, int>();
var p = (long)1e9 + 7;
var answer = 0L;
if (Math.Abs(N - M) < 2)
{
var npn = Enumeration.Fractorial(N, p);
var mpm = Enumeration.Fractorial(M, p);
answer = npn * mpm % p;
if (N == M)
{
answer *= 2;
answer %= p;
}
}
Console.WriteLine(answer);
}