I have a data frame like this:

```
 city   year value
   <chr> <dbl> <dbl>
 1 la        1    NA
 2 la        2    NA
 3 la        3    NA
 4 la        4    20
 5 la        5    25
 6 nyc       1    18
 7 nyc       2    29
 8 nyc       3    24
 9 nyc       4    17
10 nyc       5    30

```

I would like to remove any cities that don't have a complete 5 years worth of data. So in this case, I'd like to remove all rows for city la despite the fact that there is data for years 4 and 5, resulting in the following data frame:

```
 city   year value
  <chr> <dbl> <dbl>
1 nyc       1    18
2 nyc       2    29
3 nyc       3    24
4 nyc       4    17
5 nyc       5    30

```

Is this possible? Thanks in advance.