View Compilation Error

0_0_30423276_14020.cpp: In function 'll fun(ll, ll, ll)':
0_0_30423276_14020.cpp:14:47: error: too few arguments to function 'll fun(ll, ll, ll)'
         res=min(res,18*(n/2)*(n/2)*a+7*fun(n/2)); 
                                               ^
0_0_30423276_14020.cpp:10:4: note: declared here
 ll fun(ll n,ll a,ll b)
    ^