Could somebody please help me. I would be so grateful. I have looked at so many formulae including if and and, sumif, vlookups, sumproduct without success

I have a client (let's say a travel company)

The headings are Customer, Destination and Fuel in Litres

They want Excel to look down the columns (there will be many entries) and work out how many litres of fuel have been used by flight companies to certain destinations

So in my example, what is the total number of litres of fuel used by KLM flying to ALC, the the total number of litres of fuel used by KLM flying to AGP, the total number of litres of fuel used by KLM flying to IBZ etc etc

Customer Destination Fuel Litres
KLM ALC 250,000
KLM AGP 140,000
KLM ALC 250,000
KLM AGP 140,000
KLM IBZ 120,000
MY TRAVEL TFS 160,000
MY TRAVEL CFU 135,000
THOMSONFLY ALC 250,000
THOMSONFLY AGP 140,000
THOMSONFLY IBZ 120,000
THOMSONFLY ALC 250,000
THOMSONFLY ALC 250,000
THOMSONFLY ALC 250,001
THOMSONFLY ALC 250,002
VIRGIN CFU 135,000
VIRGIN ALC 250,000
VIRGIN IBZ 120,000
VIRGIN ALC 250,000
VIRGIN IBZ 120,000