int fastfib(int n)
{
  int i, fib, p = 1, q = 0;
  if(n < 1){
    return 0;
  }else if(n == 1){
    return 1;
  }else{
    for(i = 2; i <= n; i++){
      fib = p + q;
      q = p;
      p = fib;
      
    }
    return fib;
  }
}
