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#[cfg(test)]
mod tests {
    #[test]
    fn it_works() {
        assert_eq!(2 + 2, 4);
    }
}

mod repunit {
    pub fn convert(repnum: usize) -> usize {
        let rep1: String = "1".to_string();
        let rep2 = rep1.repeat(repnum);
        let repunit: usize = rep2.to_string().parse().unwrap();
        return repunit;
    }
    pub fn restore(repunit: usize) -> usize {
        let rep3: String = repunit.to_string();
        let rep4: &str = &rep3;
        let repnum: usize = rep4.match_indices("1").count();
        return repnum;
    }
}