Consider inequality
This inequality is equivalent to inequality 
This means that 
The greatest integer number n, such that
when dividing by 7 gives the remainder 4 is 39. Then subtract 7, you get 32, then 25 and so on.
When n=-39, -32, -25, -18, -11, -4, 4, 11, 18, 25, 32, 39 then dividing by 7 the remainder is 4.
Answer: 12 integers.