JERUSALEM (AP) - At Leyad Ha Universita high school, the red and blue letters on a peace collage greet visitors with a stock but heartfelt plea: ''Give Peace a Chance.''

In a 10th-grade current affairs class, teacher Michal Shavit began debate on the recent accord with the PLO by asking his Israeli students to literally line up - for or against.

Only three of the 40 students lined up against the pact - and they did so only after coaxing by Shavit. The majority was enthusiastic.

''When a country occupies another people for more than 20 years, the society gets rotten, the economy falls apart and people don't want to serve in the army anymore,'' said Leonid Meirson.

He and his 15- and 16-year-old classmates will face mandatory service in the army after graduation - three years for men and two for women.

Leyad Ha Universita serves Jerusalem's elite - standards are high and equipment is new. Only the wooden desks, long since stripped of varnish, show signs of age. Students would fit in many American campuses - tank tops, T- shirts and jeans are standard garb.

Across town at the Mamouniya School in Arab east Jerusalem, the dress is different. The ''mandil'' or head scarf adopted as the hallmark of observant Muslim women is common among its teachers and 1,400 female students.

Attitudes are somewhat different, too. In an 11th-grade English language class of Nazek Awadallah, the accord won a much slimmer majority - 20 of the 38 students.

Supporters among the 16- and 17-year-old girls argued that Palestinians had to be pragmatic.

''We are living with the Israelis in the same country. This is a reality we cannot ignore,'' said Ranya Dabash.

Opponents used stronger language.

''This is treason. ... No to peace with Jews,'' said Safaa Alan, wearing a white mandil.

She said she expected opponents to assassinate PLO chief Yasser Arafat just as they did Egyptian President Anwar Sadat, who was killed by Islamic militants opposed to his signing of the first Arab peace agreement with Israel.

About 1,400 girls attend the well-tended, three-story stone school that is funded by the city. Most are from middle- or lower-income families, and many have been activists in the Palestinian uprising that began in December 1987.

The streets outside the walled Mamouniya school, named after the son of a Caliph who was known for his skills in science, have been a battleground. Dozens of students have been arrested or tear-gassed in frequent stone- throwing clashes with police.

There are some lingering signs of the conflict, with most slogans painted over by police. One that remains is from the leftist Popular Front: ''We call on students to reject the conspiracy of Gaza and Jericho.''

Debate was sharp when a reporter asked if they would now agree to having Jewish friends.

''Why not?'' asked Alaa Awadallah. ''On a bus in Tel Aviv, I spoke with an Israeli family. ... They were very nice people. They are people, and we are people.''

But Alan countered that too much blood had been spilled. ''It is impossible for me to have a Jewish friend,'' she said. ''Their parents killed my friends and my people.''

''Even so,'' said Awadallah, ''the children are not responsible for the actions of their parents. We have also killed Israelis.''

At Leyad Ha Universita, the debate momentarily crumbled into a shouting match with opponents claiming the PLO could not be trusted and the supporters arguing that Israel had to take the risk.

''It's not just Gaza they want,'' Oded Ben-Naim said. ''The PLO gets peace and the (West Bank and Gaza) just for recognizing us.''

Rachel Cohen, throwing back her waist-long red hair, said, ''My hope is there will be two states, side by side. We have to take the chance, and though it may be hard and maybe even not good, it is better than very bad.''

In the Leyad Ha Universita, discussion of the Israel-PLO accord is part of a current affairs program encouraged by the Ministry of Education. A kit sent to schools includes fact sheets on Palestinians, editorials for and against the issue, classroom debate strategies and model questions.

But debate on hot political topics is not encouraged in the Arab schools of east Jerusalem.

Jamil Abu Tomeh, principal of the Mamouniya school, said fostering debate in the classroom could bring warring slogans back to the walls and provoke violence from hard-line opponents of the agreement.

''In Israeli schools, they oppose with words, but here they oppose with knives,'' he said. ''If we debate it, they will bring thugs using knives in the schools.''

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