use proconio::{fastout, input};

#[fastout]
fn main() {
    input! {
        a: u16,
        b: u16,
        c: u16,
        d: u16,
        m: u16,
    }

    println!("{}", output(solve(a, b, c, d, m)));
}

fn solve(a: u16, b: u16, c: u16, d: u16, m: u16) -> u16 {
    if (a + c) / m != (b + d) / m {
        m - 1
    } else {
        (b + d) % m
    }
}

fn output(ans: u16) -> u16 {
    ans
}