Three inventories (S1,S2,S3) serves four shops (T1,T2,T3,T4). 
The capacity of the inventories and the order of the shops in corresponding
units is the following:

S1	S2	S3
-------------------
135	56	93

T1	T2	T3	T4
---------------------------
62	83	39	91

The price of the transportation of a unit can be seen in the following
table.

   |	T1	T2	T3	T4
---+--------------------------------
S1 |	132	-	97	103
S2 |	85	91	-	-
S3 |	106	89	100	98

A) How to fulfill all the orders with minimal cost?

B) How the solution changes if there can be transportation between shops and
between inventories.

Transportation cost:
S1 -> S3 55
S1 -> S2 20
S2 -> S1 35
S3 -> S2 25

T2 -> T1 15
T3 -> T2 12
T2 -> T3 12
T1 -> T3 20
T3 -> T1 25
T1 -> T4 10