The Russian alphabet is not phonetic. а can be pronounced а, и, ы; е can be pronounced и, ё, э, and so on, and most consonants can be pronounced in two ways depending on the vowel that follows, or the presence of ь. You need to know where the tonic accent lies in every word to be able to pronounce it, because the position of a vowel w.r.t. the accent modifies its pronunciation. It is more phonetic than English or French, but less than Belorussian or Finnish or Spanish.