/in/foo.cc: In function 'int find_father(int)':
/in/foo.cc:14:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:18:18: warning: 'n' is used uninitialized in this function [-Wuninitialized]
  for(int i = 1;i < n + 1;i++){
                ~~^~~~~~~
/in/foo.cc:21:18: warning: 'm' is used uninitialized in this function [-Wuninitialized]
  for(int i = 1;i < m + 1;i++){
                ~~^~~~~~~
/in/foo.cc:26:18: warning: 'p' may be used uninitialized in this function [-Wmaybe-uninitialized]
  for(int i = 1;i < p + 1;i++){
                ~~^~~~~~~