I'm working on time series with a monthly demand for 5 years. Currently, I'm using naive method to forecast 12 months (h=12)and it does work very well
I want to forecast only for one month (h=1) (always with naive method) and then include this predicted value to time series and repeat this process 12 times. For example:

1. get forecast for January 2013
2. include this predicted value to time series
3. Apply naive method for the new series


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 I want to do it in R. I tried to use a loop but my problem is how to add the predicted value to my time series ?