foo.c: In function 'main':
foo.c:6:22: warning: 'n' is used uninitialized [-Wuninitialized]
    6 |         for(int i=0;i<n;i++)
      |                     ~^~
foo.c:5:8: note: 'n' was declared here
    5 |    int n,a[10000],b[10000];
      |        ^

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