foo.c: In function 'main':
foo.c:14:17: warning: 'f' may be used uninitialized [-Wmaybe-uninitialized]
   14 |                 printf("%d ",f+1);
      |                 ^~~~~~~~~~~~~~~~~
foo.c:4:23: note: 'f' was declared here
    4 |         int m,n,i,k,b,f;
      |                       ^

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