Sub First()

Dim i As Integer
Dim j As Integer
Dim target As String
Dim period As Integer
For i = 2 To 298 Step 1
    Worksheets(2).Activate
    target = Cells(i, 4)
    period = Cells(i, 3)
    
    Worksheets(3).Activate
    For j = 2 To 9 Step 1
        If (Cells(j, 1) = target) Then
            If (Cells(j, 2) < period) Then
                period = Cells(j, 2)
                Worksheets(2).Activate
                Cells(i, 3) = period
                Exit For
            End If
        End If
    Next j
Next i
End Sub
Sub Third()
Dim period As Date
Dim idOfBT As Long 'BT - Business Trip
Dim idOfTheNextBT As Long
j = 1
i = 2

idOfBT = 0



 Do While Cells(i, 1) <> ""
    If Cells(i, 1) <> idOfBT Then
        'new BT
        j = j + 1
        idOfBT = Cells(i, 1)
        Worksheets(2).Activate
        period = Cells(j, 2) + Cells(j, 3)
        Worksheets(1).Activate
    End If
    'correction
    k = i + 1
    Do While (Cells(k, 2) <> Cells(i, 2)) And (Cells(k, 2) <> "") 'searching the next BT's id of accociate
        k = k + 1
    Loop
    If Cells(k, 2) = "" Then
        i = i + 1
    Else
        idOfTheNextBT = Cells(k, 1)
        Worksheets(2).Activate
        q = j + 1
        Do While Cells(q, 1) <> idOfTheNextBT 'searching the row with information about the next BT of accociate
            q = q + 1
        Loop
        periodOfTheNextBT = Cells(q, 2)
        Worksheets(1).Activate
        If period < periodOfTheNextBT Then
            i = i + 1
        Else
            Rows(k).Delete
            i = i + 1
        End If
    End If
Loop

End Sub