#[macro_use]
mod input {

use std;
use std::io;

const SPLIT_DELIMITER: char = ' ';

#[macro_export]
#[allow(unused_macros)]
macro_rules! input {
    ( $($x:expr ),*) => {
        {
            let temp_str = input_line_str();
            let mut split_result_iter = temp_str.split_whitespace();
                $(
                let buf_split_result = split_result_iter.next();
                let buf_split_result = buf_split_result.unwrap();
                    ($x) = buf_split_result.parse().unwrap();
                )*
        }
    };
}

#[allow(dead_code)]
pub fn input_line_str() -> String {
    let mut s = String::new();
    io::stdin().read_line(&mut s).unwrap();
    s.trim().to_string()
}

#[allow(dead_code)]
pub fn p<T>(t: T)
where
    T: std::fmt::Display,
{
    println!("{}", t);
}

#[allow(dead_code)]
pub fn input_vector2d<T>(line: usize) -> Vec<Vec<T>>
where
    T: std::str::FromStr,
{
    let mut v: Vec<Vec<T>> = Vec::new();

    for _ in 0..line {
        let vec_line = input_vector();
        v.push(vec_line);
    }
    v
}

#[allow(dead_code)]
pub fn input_vector<T>() -> Vec<T>
where
    T: std::str::FromStr,
{
    let mut v: Vec<T> = Vec::new();

    let s = input_line_str();
    let split_result = s.split(SPLIT_DELIMITER);
    for z in split_result {
        let buf = match z.parse() {
            Ok(r) => r,
            Err(_) => panic!("Parse Error"),
        };
        v.push(buf);
    }
    v
}

#[allow(dead_code)]
pub fn str2vec(s: &str) -> Vec<char> {
    let mut v: Vec<char> = Vec::new();
    for c in s.chars() {
        v.push(c);
    }
    v
}
}

use input::*;

fn main() {
    let (sx, sy, tx, ty): (isize, isize, isize, isize);
    input!(sx, sy, tx, ty);
    let (mut x, mut y) = (sx, sy);
    let mut stage = 0;

    while stage != 8 {
        if stage == 0 {
            //txへ向かう
            if x == tx {
                stage += 1;
            } else if x < tx {
                print!("R");
                x += 1;
            } else {
                print!("L");
                x -= 1;
            }
        } else if stage == 1 {
            //tyへ向かう
            if y == ty {
                stage += 1;
            } else if y < ty {
                print!("U");
                y += 1;
            } else {
                print!("D");
                y -= 1;
            }
        } else if stage == 2 {
            //sxへ向かう
            if x == sx {
                stage += 1;
            } else if x < sx {
                print!("R");
                x += 1;
            } else {
                print!("L");
                x -= 1;
            }
        } else if stage == 3 {
            //syへ向かう
            if y < sy {
                print!("U");
                y += 1;
                if y == sy {
                    print!("U");
                    y += 1;
                    stage += 1;
                }
            } else {
                print!("D");
                y -= 1;
                if y == sy {
                    print!("D");
                    y -= 1;
                    stage += 1;
                }
            }
        } else if stage == 4 {
            //tx+1 or tx-1へ向かう
            if x < tx {
                print!("R");
                x += 1;
                if x == tx {
                    x += 1;
                    print!("R");
                    stage += 1;
                }
            } else {
                print!("L");
                x -= 1;
                if x == tx {
                    x -= 1;
                    print!("L");
                    stage += 1;
                }
            }
        } else if stage == 5 {
            //tyへ向かう
            if y < ty {
                print!("U");
                y += 1;
                if y == ty {
                    y += 1;
                    x -= 1;
                    print!("LU");
                    stage += 1;
                }
            } else {
                print!("D");
                y -= 1;
                if y == ty {
                    x += 1;
                    y -= 1;
                    print!("RD");
                    stage += 1;
                }
            }
        } else if stage == 6 {
            //sx-1 or sx+1へ向かう
            if x < sx {
                print!("R");
                x += 1;
                if x == sx {
                    x += 1;
                    print!("R");
                    stage += 1;
                }
            } else {
                print!("L");
                x -= 1;
                if x == sx {
                    x -= 1;
                    print!("L");
                    stage += 1;
                }
            }
        } else if stage == 7 {
            //syへ向かう
            if y < sy {
                print!("U");
                y += 1;
                if y == sy {
                    x += 1;
                    print!("L");
                    stage += 1;
                }
            } else {
                print!("D");
                y -= 1;
                if y == sy {
                    x -= 1;
                    print!("R");
                    stage += 1;
                }
            }
        }
    }
    println!("");
}

Measured memory_bytes: 4352