OK, I changed loading data from dict to matrix.

I suppose this is the way to declare those variables and constraints:

```
@variable(prmx,
isCovered[1:_ROWS, 1:_COLUMNS],
Bin)
@variable(prmx,
isAntenna[1:_ROWS, 1:_COLUMNS],
Bin)
@objective(
prmx,
Min,
sum(isCovered[i, j] * isHouse[i, j]
for i in 1:_ROWS, j in 1:_COLUMNS
)
)
@constraint(
prmx,
sum(isCovered[i, j] * isHouse[i, j]
for i in 1:_ROWS, j in 1:_COLUMNS
)
>= _TOTAL * 0.7
)
```