View Compilation Error

0_0_39075572_14295.cpp: In function 'long long int mid(long long int, long long int)':
0_0_39075572_14295.cpp:7:16: error: 'mod' was not declared in this scope; did you mean 'mid'?
    7 |   long long s= mod(a,b/2)%10;
      |                ^~~
      |                mid
0_0_39075572_14295.cpp: In function 'int main()':
0_0_39075572_14295.cpp:18:8: error: 'mod' was not declared in this scope; did you mean 'mid'?
   18 |  cout<<mod(N,N)<<endl;
      |        ^~~
      |        mid