Burger shopNumber Theory Level 4
In a burger shop,you can buy a cheese burger with $7, or you could buy a extra cheese burger for $11 .( it is the most expensive burger in town :v)
What is the maximum number of money that you can't get the exact value with buying any combination of those 2 burgers
Example : $14 you could buy 2 cheese burgers, but with $15, you can't buy the exact value.