foo.cc: In function 'int main()':
foo.cc:13:15: error: 'cin' was not declared in this scope
   13 |     int n, m; cin >> n >> m;
      |               ^~~
foo.cc:2:1: note: 'std::cin' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
    1 | #include <cstring>
  +++ |+#include <iostream>
    2 | 
foo.cc:16:5: error: 'cout' was not declared in this scope
   16 |     cout << a[m];
      |     ^~~~
foo.cc:16:5: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?

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