View Compilation Error

0_0_18223131_16941.cpp: In function 'int main()':
0_0_18223131_16941.cpp:9:1: error: 'LL' was not declared in this scope
 LL ans = (2 * n * n + (n&1?-1:1)) / 8; 
 ^
0_0_18223131_16941.cpp:10:3: error: 'ans' was not declared in this scope
 f(ans <= m)  
   ^
0_0_18223131_16941.cpp:10:11: error: 'f' was not declared in this scope
 f(ans <= m)  
           ^
0_0_18223131_16941.cpp:12:9: error: 'else' without a previous 'if'
         else  
         ^