I have an issue I can't seem to figure out

I have a data frame like this 

```
df <- data.frame(c(rep_len("a",3), "b", "b"), c(rep_len(55, 3), 44, 44),c(rep_len(12, 3), 6, 6), c("na", 2, "na", 3, "na"), c("na", "na", 4, "na", 8), c(5, "na", "na", "na", "na"))
names(df) <- c("street", "latitude", "longitude", "A", "B", "C")

street latitude longitude     A   B   C
    a       55         12    na  na   5
    a       55         12     2  na  na
    a       55         12    na   4  na
    b       44          6     3  na  na
    b       44          6    na   8  na

```

and I guess what I'm looking for is a way to collapse rows with identical values in 'street', 'latitude', 'longitude' so the data frame looks like this 

```
street latitude longitude     A   B   C
     a       55        12     2   4   5
     b       44         6     3   8  na

```

My best attempt is this:

```
df %>%
  group_by(street) %>%
  summarise_each(funs(first))

```

But its not quite right. Have any ideas?