I have these two sheets (as an example)

Sheet 1 :

..........A................ B........... C .........D
......Product .........Total
......Codes ..........sales
3 ..apples
4..pears
5 ..bananas

Sheet 2:


..............s...................t.............. u ...............v
.............Product... Sales
.............Codes
48 ......apples........ 20
49...... pears .........15
50..... bananas...... 23
51 ......apples .........8
52 .....apples .........13
53 ...bananas .........15

In column b on sheet 1, i wish to total the sales values - so for example
column b 3 i wish to add up ALL the sales of apples (20+8+13 =answer 41)....

What formula do i need to put in column b3 to achieve this?

many thanks