foo.cc: In function 'void work()':
foo.cc:122:21: error: cannot bind non-const lvalue reference of type 'int&' to a value of type 'll' {aka 'long long int'}
  122 |         ll Res=Eval(a);
      |                     ^
foo.cc:12:14: note:   initializing argument 1 of 'll Eval(int&)'
   12 | ll Eval(int& St)
      |         ~~~~~^~

[Hydro](https://hydro.ac)提供评测服务