The following result is obtained when all the variables are required to be integer. Note that the letter I precedes the index for variables that are required to be integer.
The LP dialog has an entry that indicates the number of leading variables that are to be integer. The leading variables are those with the lowest indices. Variables other that the leading ones can be made integer by placing the letter I or any word beginning with I in the cells normally holding the variable indices. The image below shows the solution when the two leading variables are integer and P5 is made integer by placing the word "integer" in its index field.