What am I doing wrong?

[SuperSparks]

Can anyone tell me what is wrong with this code, please?

If Counter < 2 AndAlso txtSin.Text <> "" Then Sine = CDbl(txtSin.Text)
            Counter += CByte(1)
           elseIf Counter < 2 AndAlso txtCos.Text <> "" Then Cosine = CDbl(txtCos.Text)
 
            End If

Both the ElseIf and End If statements have the blue squiggly lines under them with the tooltip saying they must be preceded by a matching If statement