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Brazilians have endured more than three years of near daily revelations about the political elite getting kickbacks, bribes and illegal campaign financing, first through the sprawling Car Wash probe at state-run oil giant Petrobras and now through investigations at other companies.

The result has been a widespread distrust of the political class that analysts say could give a competitive edge to candidates without the smudge of corruption in the 2018 presidential elections.

The renowned Datafolha polling institute in early May identified 20 top potential candidates for president. Datafolha interviewed 2,781 people April 26-27 in 172 cities and had a 2 percent margin of error

Here is a look at the top five potential candidates in the pool of 20 not tainted by corruption:

MARINA SILVA

Marina Silva currently polls second, but in a run-off against her one-time mentor and now adversary, Luiz Inacio Lula da Silva, she would beat the former president. The 59-year-old former environmental minister under Silva is respected by sectors on the right and by part of the left. She finished third in the two previous elections with about 20 percent in each. A major issue for her is her recently created Sustainability Network Party. Brazil's electoral law gives free air time to candidates, and how much depends on the number of elected officials a party has in the lower Chamber of Deputies in Congress. Marina Silva's health is also a question mark after she was hospitalized over the weekend with chest pains.

JAIR BOLSONARO

The 62-year-old congressman is the main voice of Brazil's far-right, and currently polls second in a tie with Marina Silva, but far from former President Lula da Silva in a run-off. Bolsonaro is in his sixth term, and his extremist views have made him such a household name that three of his sons have also been elected for jobs in legislative bodies. He has gained popularity among ultra conservatives by saying he would appoint several members of the military for his cabinet if he wins. Bolsonaro has tried to moderate his tone for the last year and backed market friendly ideas for the economy to sound more electable. But he currently is at odds with other leaders of his Social Christian Party, which holds only 10 deputies and one senator.

SERGIO MORO

Even without campaigning or ever saying that he is interested in the presidency, the Car Wash investigation judge polls fourth. At age 44, he is hailed as a hero by many Brazilians after jailing scores of corrupt politicians and businessmen. He has also been harshly criticized by many for keeping defendants in jail while they await trial and heavily using plea bargains to build cases. Supporters of a Moro run for office, however, have a problem: the introvert judge has shown no interest in politics.

JOAO DORIA

The new mayor of Sao Paulo won his first election only last October, which allows him to argue he is still an outsider. The 59-year-old businessman and former host of the Brazilian edition of "The Apprentice" has been compared to U.S. President Donald Trump for his aggressive rhetoric and rejection of traditional politics. Doria says he is more of a moderate like former New York Mayor Michael Bloomberg. He is currently polling fifth, behind Luiz Inacio Lula da Silva, Marina Silva, Bolsonaro and Moro, according to Datafolha. And he faces big hurdles to even running for president: he has repeatedly promised to finish his mayoral term and Sao Paulo Gov. Geraldo Alckmin, Doria's mentor and a heavyweight in their party, is a presidential hopeful. But members of Doria's staff want him to run.

CIRO GOMES

The left-leaning 59-year-old has the strongest political resume among untainted candidates: he was mayor of Fortaleza, governor of the state of Ceara, federal deputy, twice a minister and business executive of a Brazilian multinational. However, he has lost two previous presidential bids. He has been criticized for being a poor communicator and blasting adversaries in a way that makes him appear more radical than he is. Gomes is currently polling fifth, tied with Doria.