private string FillPattern(string wildcardPattern)
{
StringBuilder sb = new StringBuilder();
for (int i = 0; i < wildcardPattern.Length; i++)
{
switch (wildcardPattern[i])
{
case 'N':
sb.Append(N());
break;
default:
sb.Append(wildcardPattern[i]);
break;
}
}
return sb.ToString();
}