The four-digit number 1234 can be transformed into 1541 by the following transformation: 1234\begin{array}\\12+1+2\\\rightarrow\\34+3+4\end{array}1541 now has a four-digit number, Through the above method, it is transformed into 3779, so what is the original four-digit number.
四位数1234可通过下面的变换变成1541：1234\begin{array}\\12+1+2\\\rightarrow\\34+3+4\end{array}1541现在有一个四位数，通过以上方法变换成3779，那么原来的这个四位数是多少．
<result>3_271</result>