int i = 0;
int countRow = 0;
List<string> sheetsNames = new List<string>();
List<string> fn = new List<string>();
foreach (Worksheet wSheet in wBook.Sheets)
{
i = ++i;
sheetsNames.Add(wSheet.Name);
Worksheet ss = wBook.Sheets[i];
for (int j = 6; j < ss.UsedRange.Rows.Count; j++)
{
Range range = ss.get_Range(i, j);
fn = range.Value;
}

}