```r
totals <- tidy_tweets %>% 
  group_by(person, id) %>% 
  summarise(rts = first(retweets)) %>% 
  group_by(person) %>% 
  summarise(total_rts = sum(rts))

totals
```

```
## # A tibble: 2 x 2
##   person total_rts
##   <chr>      <dbl>
## 1 David      13014
## 2 Julia       1750
```