static void Main(string[] args)
{
var wh = Input.ar;
var com = new Calculation.Combination(wh[0] + wh[1] - 2);
WriteLine(com.Comb(wh[0] + wh[1] - 2, wh[0] - 1));
}
static void Main(string[] args)
{
var hwab = Input.ar;
var com = new Calculation.Combination(hwab[0] + hwab[1]);
var sum = 0L;
for (var i = hwab[3]; i < hwab[1]; i++)
{
sum += (long)com.Comb(hwab[0] - hwab[2] + i - 1, i) * com.Comb(hwab[2] + hwab[1] - i - 2, hwab[1] - i - 1);
sum %= Input.MOD;
}
WriteLine(sum);
}
