foo.c: In function 'main':
foo.c:5:9: error: expected identifier or '(' before numeric constant
    5 |     int 2020,2;
      |         ^~~~
foo.c:6:9: error: 'retern' undeclared (first use in this function)
    6 |         retern 29
      |         ^~~~~~
foo.c:6:9: note: each undeclared identifier is reported only once for each function it appears in
foo.c:6:15: error: expected ';' before numeric constant
    6 |         retern 29
      |               ^~~
      |               ;

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