D 1

D 2

D 3

D 4

Capacity

S 1

a 11

a 12

a 13

a 14

a 1

S 2

a 21

a 22

a 23

a 24

a 2

S 3

a 31

a 32

a 33

a 34

a 3

Demand

b 1

b 2

b 3

b 4