/in/foo.cc: In function 'int main()':
/in/foo.cc:28:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf( "%d" , &n ) ; an = 0 ;
                            ^
/in/foo.cc:30:49: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
                 scanf( "%d%d" , S + i , T + i ) ; T[ i ] += S[ i ] ;
                                                 ^