comefrom: <qiyuangong>509_Fibonacci_Number_1.java
code: public int fib(int N) {
          if (N == 0) return 0;
          if (N == 1) return 1;
          return fib(N - 1) + fib(N - 2);
      }
masked: public int sample_funcname ( int N ) {
    if ( N == 0 ) return 0 ;
    if ( N == 1 ) return 1 ;
    return fib ( N - 1 ) + fib ( N - 2 ) ;
  }
  