/in/foo.cc:3:1: error: 'usig' does not name a type
    3 | usig namespace std;
      | ^~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:7:5: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    7 |     cin>>a>>b>>c;
      |     ^~~
      |     std::cin
In file included from /in/foo.cc:1:
/usr/include/c++/12/iostream:60:18: note: 'std::cin' declared here
   60 |   extern istream cin;           /// Linked to standard input
      |                  ^~~
/in/foo.cc:11:15: error: expected ';' before 'if'
   11 |         minn=b
      |               ^
      |               ;
   12 |     if(c<b)
      |     ~~