As initial value of a new map expression with ()+-/* operators can be given. These operators work on numbers, or on maps. If maps are given, then the new value for a given graph element will be calculated using the value from the given maps that belong to that graph element.

 c LEMON max flow problem

 p max 7 9

 n 1 s

 n 7 t

 a 1 2 3

 a 1 3 2

 a 1 4 1

 a 2 5 3

 a 3 5 2

 a 3 7 5

 a 3 6 3

 a 4 6 1

 a 5 7 2

 a 6 7 4