foo.c:2:8: error: expected declaration specifiers or '...' before string constant
    2 | printf("hello, world\n");
      |        ^~~~~~~~~~~~~~~~
foo.c:3:1: warning: data definition has no type or storage class
    3 | n=int(input())
      | ^
foo.c:3:1: warning: type defaults to 'int' in declaration of 'n' [-Wimplicit-int]
foo.c:3:3: error: expected expression before 'int'
    3 | n=int(input())
      |   ^~~

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