删除具有Sal列的所有NA的观测值

Question

我的输入就像

Input = data.frame("VarA"= c("A","B","C"), Sal1 = c(NA,10,NA), Sal2 = c(NA,9,NA), Sal3 = c(8,90,NA))

所需的输出是（我想摆脱Sal1-Sal3列具有所有NA的行

Output = data.frame("VarA"= c("A","B"), Sal1 = c(NA,10), Sal2 = c(NA,9), Sal3 = c(8,90))