I want to check if the sheet exists before creating it.

```
using Excel = Microsoft.Office.Interop.Excel;

Excel.Application excel = new Excel.Application();
excel.Visible = true;
Excel.Workbook wb = excel.Workbooks.Open(@"C:\"Example".xlsx");

Excel.Worksheet sh = wb.Sheets.Add();
int count = wb.Sheets.Count;

sh.Name = "Example";
sh.Cells[1, "A"].Value2 = "Example";
sh.Cells[1, "B"].Value2 = "Example"
wb.Close(true);
excel.Quit();

```