/in/foo.cc: In function 'int getLCA(int, int)':
/in/foo.cc:66:15: error: 'log' was not declared in this scope
  k=log(1.0+b-a)/log(2.0);
               ^
/in/foo.cc: In function 'void Input()':
/in/foo.cc:74:7: warning: unused variable 's' [-Wunused-variable]
  char s[5];
       ^