View Compilation Error

0_0_21021067_18607.cpp:19:12: error: 'LL' was not declared in this scope
 double fun(LL n,LL x)
            ^
0_0_21021067_18607.cpp:19:17: error: 'LL' was not declared in this scope
 double fun(LL n,LL x)
                 ^
0_0_21021067_18607.cpp:19:21: error: expression list treated as compound expression in initializer [-fpermissive]
 double fun(LL n,LL x)
                     ^
0_0_21021067_18607.cpp:20:1: error: expected ',' or ';' before '{' token
 {
 ^
0_0_21021067_18607.cpp: In function 'double solve(int, int, int)':
0_0_21021067_18607.cpp:34:21: error: 'LL' was not declared in this scope
         return fun((LL)n, (LL)b*q*q*q);
                     ^
0_0_21021067_18607.cpp:34:31: error: expected ')' before 'b'
         return fun((LL)n, (LL)b*q*q*q);
                               ^
0_0_21021067_18607.cpp:34:38: error: 'fun' cannot be used as a function
         return fun((LL)n, (LL)b*q*q*q);
                                      ^