p-value calculation

hello everybody

i'm very new at using R so probably this is a very stupid question.
I have a problem calculating a p-value. When i do this with excel i
can use the method CHIDIST for 1.2654 with 1 freedom degree i get the
answer 0.261

i just want to do the same thing in R but i can't find a method.
can somebody help me

friendly regards

richard