View Compilation Error

0_0_16617086_20887.cpp: In function 'int zhaodian(int, int)':
0_0_16617086_20887.cpp:18:77: error: 'finddian' was not declared in this scope
  for(int k=last[x];k;k=a[k].next) if(a[k].y!=fa) ans^=finddian(a[k].x,a[k].y);
                                                                             ^