WARSAW, Poland (AP) _ For the next three weeks, the only sounds to be heard in Philharmonic Hall will be Chopin and applause as young pianists compete for a chance to make their careers.

The 13th International Frederic Chopin Piano Competition, with a $25,000 top prize, begins Sunday among 140 contestants from 33 countries. Alexei Sultanov, 26, of Russia, who has won several other contests, is a favorite.

The competition has been held every five years since 1927 _ except for a 1937-49 hiatus _ and sets a standard for interpreting the music of the 19th-century Polish-born composer.

Chopin's works are considered difficult because of their changing tempos, based on traditional Polish dances such as the mazurka and polonaise.

Joanna Switlik, a pianist at the Warsaw Music Academy, said offers from concert organizers and record companies pour in for the top three winners, securing them a career. The prizes for second and third place are $20,000 and $15,000 respectively.

Poland and Japan have entered the most pianists, 23 each. There are 15 competitors from Russia and seven from the United States.

Polish fans are rooting for either Filip Wojciechowski, 25, or Rafal Luszczewski, 24, whose teacher, Andrzej Jasinski, also trained the 1975 winner, Krystian Zimerman.

Kimio Sano, a music critic and secretary of the Frederic Chopin Society of Japan, mentioned top prospects Masaru Okada, 21, and Koji Oikawa, a semifinalist in the last Chopin competition.

Music lovers fill the 1,072-seat Philharmonic Hall to cheer their favorites, but the public's preferences are not always those of the jury, whose members favor adherence to tradition.

In 1980, when Ivo Pogorelic of Yugoslavia was knocked out before the final round, jury member Martha Argerich of Argentina, who had won the competition in 1965, resigned in protest.

Pogorelic won the hearts of the public, but treated the musical text with too much liberty, said Albert Grudzinski, chairman of the Chopin Society, which organizes the competition.

But Sano felt ``sports-like technique'' dominates the recitals.

``Is it really so good to be able to manipulate one's fingers like a machine gun?'' Sano said in Tokyo. ``In my view, the foundation of the judging should be whether one can express the style, the sense of the form.''

Previous winners of the competition include Italy's Maurizio Pollini in 1960, Garrick Ohlsson of the United States in 1970, and Lev Oborin of the Soviet Union in the 1927 inaugural competition.