fn main() {
    let mut xx = String::new();
    std::io::stdin().read_line(&mut xx).ok();
    let xx: Vec<u64> = xx.split_whitespace().flat_map(str::parse).collect();

    let max = xx[3] / (1 + xx[2]);
    let answer = max.min(xx[0]).min(xx[1] / xx[2]);

    println!("{}", answer);
}