/in/foo.cc:5:33: error: too many initializers for 'int [3]'
 int a[4]={2,3,5,7},b[3]={1,3,7,9};
                                 ^
/in/foo.cc: In function 'int dfs(int, int)':
/in/foo.cc:19:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^