Error incomplete universal character name \U

I'm trying to write a C++ program that alters a .txt file. However when I run it I get a strange error.

The error:

6:20 C:\Dev-Cpp\Homework6.cpp incomplete universal character name \U

My code:

#include <iostream>
#include <fstream>
using namespace std;

int main () {
  ofstream myfile ("C:\Users\My Name\Desktop\test\input.txt");
  if (myfile.is_open())
  {
    myfile << "This is a line.\n";
    myfile << "This is another line.\n";
    myfile.close();
  }
  else cout << "Unable to open file";
  return 0;
}

What am I doing wrong?