foo.cc: In function 'void dfs()':
foo.cc:23:20: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
    if(i%5) m+=(1<<i-1);
                   ~^~
foo.cc:24:23: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
    if(i%5!=4) m+=(1<<i+1);
                      ~^~
foo.cc: In function 'int main()':
foo.cc:42:7: warning: unused variable 'ant' [-Wunused-variable]
   int ant=-1;
       ^~~
foo.cc:38:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~

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