one has an accent marked and the other not, with different pronunciation and meaning—such as ("pear tree") and ("but"), and ("Pope") and ("dad"); the latter example is also valid for Catalan. In Bulgarian, the grave accent sometimes appears on the vowels , , , , , and to mark stress. It most commonly appears in books for children or foreigners, and dictionaries—or to distinguish between near-homophones: (, "steam/vapour") and (, "cent/penny, money"), (, "wool") and (, "wave"). In Macedonian the stress mark is orthographically required to distinguish homographs (see ) and is put mostly on the vowels е and и. Then, it forces the stress on the accented word-syllable instead of having a different syllable in the stress group getting accented. In turn, it changes the pronunciation and the whole meaning of the group. Ukrainian, Rusyn, Belarusian, and Russian used a similar system until the first half of the 20th century. Now the main stress is preferably marked with an acute, and the role of the grave is limited to marking secondary stress in compound words (in dictionaries and linguistic literature). In Croatian, Serbian, and Slovene, the stressed syllable can be short or long and have a rising or falling tone. They use (in dictionaries, orthography, and grammar books, for example) four different stress marks (grave, acute, double grave, and inverted breve) on the letters a, e, i, o, r, and u: à è ì ò r̀ ù. The system is identical in both Latin and Cyrillic scripts. Unicode forgot to encode R-grave when encoding the letters with stress marks. In modern Church Slavonic, there are three stress marks (acute, grave, and circumflex), which formerly represented different types of pitch accent. There is no longer any phonetic distinction between them, only an orthographical one. The grave is typically used when the stressed vowel is the last letter of a multiletter word. In Ligurian, the grave accent marks the accented short vowel of a word in (sound ), (sound ), (sound ) and (sound ). For , it indicates the short sound of , but may not be the stressed vowel of the word. Height The grave accent marks the height or openness of the vowels e and o, indicating that they are pronounced open: è (as opposed to é ); ò (as opposed to ó ), in several Romance languages: Catalan uses the accent on three letters (, , and