foo.c: In function 'main':
foo.c:8:20: warning: unused variable 'b' [-Wunused-variable]
    8 |         int a = 0, b = 0;
      |                    ^
foo.c:8:13: warning: unused variable 'a' [-Wunused-variable]
    8 |         int a = 0, b = 0;
      |             ^
foo.c:7:18: warning: unused variable 'n' [-Wunused-variable]
    7 |         int m=0, n=0;
      |                  ^
foo.c:7:13: warning: unused variable 'm' [-Wunused-variable]
    7 |         int m=0, n=0;
      |             ^

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