unable to user R intrepter

Hi Team,

While using %r interpreter we are getting "Prefix not found" or "R interpreter not found". Can someone please help me that how can i proceed. 

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%r
foo <- TRUE
print(foo)
bare <- c(1, 2.5, 4)
print(bare) double <- 15.0 print(double)

output: prefix not found 

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Regards
Amit Kumar Gorai

+91-8884346691

Timing 11:00AM-07:00PM IST