Unable to mark labels

I am solving the following question. I want to label the data. I used the 
following code.

data82 <- read.table(file="/home/rajat/R/8_2_rtg.txt",header=T)

data82 <- data.frame(data82)

data82

low_sat med_sat high_sat contact housing
1      65      54      100       1       1
2     130      76      111       1       2
3      67      48       62       1       3
4      34      47      100       2       1
5     141     116      191       2       2
6     130     105      104       2       3

sapply(data82,class)

low_sat   med_sat  high_sat   contact   housing 
"integer" "integer" "integer" "integer" "integer"

data82$contact<-factor(contact,labels=c("low","high"))

When I run the last line I  get  the following  message --

ERROR:  object "contact" not found


Any suggestions