foo.c: In function 'main':
foo.c:6:37: warning: variable 'f' set but not used [-Wunused-but-set-variable]
    long long cnt, a, b, c,d,e, cna, f, g;
                                     ^
foo.c:6:22: warning: unused variable 'b' [-Wunused-variable]
    long long cnt, a, b, c,d,e, cna, f, g;
                      ^
foo.c:7:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld", &a);
     ^~~~~~~~~~~~~~~~~

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