foo.cc: In function 'int main()':
foo.cc:21:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   21 | for(int i=1;i<=m;i++) scanf("%d%d%d",&edge[i].x,&edge[i].y,&edge[i].w);
      |                       ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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