/in/foo.cc:2:7: error: 'maxn' was not declared in this scope
 int a[maxn];
       ^~~~
/in/foo.cc:3:1: error: 'll' does not name a type
 ll fib[maxn];
 ^~
/in/foo.cc: In function 'int main()':
/in/foo.cc:6:2: error: 'fib' was not declared in this scope
  fib[1] = 1;
  ^~~
/in/foo.cc:10:6: error: 'read' was not declared in this scope
  n = read;
      ^~~~
/in/foo.cc:11:2: error: 'll' was not declared in this scope
  ll x,y;
  ^~
/in/foo.cc:13:3: error: 'x' was not declared in this scope
   x = read,y = read;
   ^
/in/foo.cc:13:12: error: 'y' was not declared in this scope
   x = read,y = read;
            ^
/in/foo.cc:15:22: error: 'swap' was not declared in this scope
    if(x > y) swap(x,y);
                      ^
/in/foo.cc:16:40: error: 'lower_bound' was not declared in this scope
    int pos = lower_bound(fib+1,fib+66,y) - fib;
                                        ^
/in/foo.cc:20:20: error: 'printf' was not declared in this scope
   printf("%lld\n",x);
                    ^