foo.cc: In function 'void Kruskal()':
foo.cc:28:22: warning: left operand of comma operator has no effect [-Wunused-value]
     for(int i=1,j=0;i<=m,j<n-1;i++){
                     ~^~~
foo.cc:26:9: warning: unused variable 'cnt' [-Wunused-variable]
     int cnt=0;
         ^~~
foo.cc: In function 'int main()':
foo.cc:41:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
     ~~~~~^~~~~~~~~~~~~~
foo.cc:43:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%d",&u,&v,&c);
         ~~~~~^~~~~~~~~~~~~~~~~~~

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