foo.cc:8:2: error: stray '#' in program
 }#include <cstdio>
  ^
foo.cc:8:3: error: 'include' does not name a type
 }#include <cstdio>
   ^~~~~~~
foo.cc: In function 'int main()':
foo.cc:20:5: error: redefinition of 'int main()'
 int main()
     ^~~~
foo.cc:5:5: note: 'int main()' previously defined here
 int main()
     ^~~~
foo.cc:28:6: warning: unused variable 'b' [-Wunused-variable]
  int b=0;
      ^
foo.cc:22:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
     ~~~~~^~~~~~~~~~~~~~
foo.cc:24:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&vn[i].id,&vn[i].num);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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