#include <bits/stdc++.h>
using namespace std;
void printar(int ar[], int s) {
  for (int i = 0; i < s; i++) cout << ar[i] << " ";
  cout << endl;
}
char cp, rp;
int cpos, rpos;
void case1() {
  int cdif, idif;
  cdif = rp - cp;
  idif = cpos - rpos;
  int dmove = min(cdif, idif);
  int tmove = max(cdif, idif);
  cout << tmove << endl;
  for (int i = 0; i < dmove; i++) {
    cout << "RD\n";
  }
  dmove = tmove - dmove;
  if (cdif > idif) {
    for (int i = 0; i < dmove; i++) {
      cout << "R\n";
    }
  } else if (idif > cdif) {
    for (int i = 0; i < dmove; i++) {
      cout << "D\n";
    }
  }
}
void case2() {
  int cdif, idif;
  cdif = rp - cp;
  idif = rpos - cpos;
  int dmove = min(cdif, idif);
  int tmove = max(cdif, idif);
  cout << tmove << endl;
  for (int i = 0; i < dmove; i++) {
    cout << "RU\n";
  }
  dmove = tmove - dmove;
  if (cdif > idif) {
    for (int i = 0; i < dmove; i++) {
      cout << "R\n";
    }
  } else if (idif > cdif) {
    for (int i = 0; i < dmove; i++) {
      cout << "U\n";
    }
  }
}
void case3() {
  int cdif, idif;
  cdif = cp - rp;
  idif = cpos - rpos;
  int dmove = min(cdif, idif);
  int tmove = max(cdif, idif);
  cout << tmove << endl;
  for (int i = 0; i < dmove; i++) {
    cout << "LD\n";
  }
  dmove = tmove - dmove;
  if (cdif > idif) {
    for (int i = 0; i < dmove; i++) {
      cout << "L\n";
    }
  } else if (idif > cdif) {
    for (int i = 0; i < dmove; i++) {
      cout << "D\n";
    }
  }
}
void case4() {
  int cdif, idif;
  cdif = cp - rp;
  idif = rpos - cpos;
  int dmove = min(cdif, idif);
  int tmove = max(cdif, idif);
  cout << tmove << endl;
  for (int i = 0; i < dmove; i++) {
    cout << "LU\n";
  }
  dmove = tmove - dmove;
  if (cdif > idif) {
    for (int i = 0; i < dmove; i++) {
      cout << "L\n";
    }
  } else if (idif > cdif) {
    for (int i = 0; i < dmove; i++) {
      cout << "U\n";
    }
  }
}
void solve() {
  cin >> cp >> cpos;
  cin >> rp >> rpos;
  if (cp <= rp and cpos >= rpos) {
    case1();
  } else if (cp <= rp and cpos <= rpos) {
    case2();
  } else if (cp >= rp and cpos >= rpos) {
    case3();
  } else {
    case4();
  }
}
int main() {
  solve();
  return 0;
}
