Defensive Merging

Merge the three data frames defined below. Your final data frame should have 9 rows and 5 columns. Hint: merge only two data frames at a time.

df1 <- data.frame(
    name = c("Mary", "Thor", "Sven", "Jane", "Ake", "Stephan",
             "Bjorn", "Oden", "Dennis"),
    treatment_gr = c(rep(c(1, 2, 3), each = 3)),
    weight_p1 = round(runif(9, 100, 200), 0)
    )
df2 <- data.frame(
    name = c("Sven", "Jane", "Ake", "Mary", "Thor", "Stephan",
             "Oden", "Bjorn"),
    weight_p2 = round(runif(8, 100, 200), 0)
    )
df3 <- data.frame(
    treatment_gr = c(1, 2, 3),
    type = c("dog-lovers", "cat-lovers", "all-lovers")
    )