#include <bits/stdc++.h>
using namespace std;
int main() {
  string s, t;
  cin >> s >> t;
  int x = s[0] - t[0];
  int y = s[1] - t[1];
  printf("%d\n", max(abs(x), abs(y)));
  if (x >= 0 && y >= 0) {
    if (abs(x) > abs(y)) {
      for (int i = 0; i < min(abs(x), abs(y)); i++) {
        printf("LD\n");
      }
      for (int i = 0; i < max(abs(x), abs(y)) - min(abs(x), abs(y)); i++) {
        printf("L\n");
      }
    } else if (abs(x) < abs(y)) {
      for (int i = 0; i < min(abs(x), abs(y)); i++) {
        printf("LD\n");
      }
      for (int i = 0; i < max(abs(x), abs(y)) - min(abs(x), abs(y)); i++) {
        printf("D\n");
      }
    } else {
      for (int i = 0; i < abs(x); i++) {
        printf("LD\n");
      }
    }
  } else if (x >= 0 && y < 0) {
    if (abs(x) > abs(y)) {
      for (int i = 0; i < min(abs(x), abs(y)); i++) {
        printf("LU\n");
      }
      for (int i = 0; i < max(abs(x), abs(y)) - min(abs(x), abs(y)); i++) {
        printf("L\n");
      }
    } else if (abs(x) < abs(y)) {
      for (int i = 0; i < min(abs(x), abs(y)); i++) {
        printf("LU\n");
      }
      for (int i = 0; i < max(abs(x), abs(y)) - min(abs(x), abs(y)); i++) {
        printf("U\n");
      }
    } else {
      for (int i = 0; i < abs(x); i++) {
        printf("LU\n");
      }
    }
  } else if (x < 0 && y >= 0) {
    if (abs(x) > abs(y)) {
      for (int i = 0; i < min(abs(x), abs(y)); i++) {
        printf("RD\n");
      }
      for (int i = 0; i < max(abs(x), abs(y)) - min(abs(x), abs(y)); i++) {
        printf("R\n");
      }
    } else if (abs(x) < abs(y)) {
      for (int i = 0; i < min(abs(x), abs(y)); i++) {
        printf("RD\n");
      }
      for (int i = 0; i < max(abs(x), abs(y)) - min(abs(x), abs(y)); i++) {
        printf("D\n");
      }
    } else {
      for (int i = 0; i < abs(x); i++) {
        printf("RD\n");
      }
    }
  } else {
    if (abs(x) > abs(y)) {
      for (int i = 0; i < min(abs(x), abs(y)); i++) {
        printf("RU\n");
      }
      for (int i = 0; i < max(abs(x), abs(y)) - min(abs(x), abs(y)); i++) {
        printf("R\n");
      }
    } else if (abs(x) < abs(y)) {
      for (int i = 0; i < min(abs(x), abs(y)); i++) {
        printf("RU\n");
      }
      for (int i = 0; i < max(abs(x), abs(y)) - min(abs(x), abs(y)); i++) {
        printf("U\n");
      }
    } else {
      for (int i = 0; i < abs(x); i++) {
        printf("RU\n");
      }
    }
  }
  return 0;
}
