View Compilation Error

0_0_36687411_25269.cpp:344:20: error: expected identifier before ')' token
 ull c(ull a, ull b,)  
                    ^
0_0_36687411_25269.cpp: In function 'void tofindans()':
0_0_36687411_25269.cpp:362:55: error: too few arguments to function 'ull c(ull, ull, int)'
         ull x=n%mod*f[n]%mod*f[n*n-n]%mod* c(n*n-i,n-1)%mod;
                                                       ^
0_0_36687411_25269.cpp:344:5: note: declared here
 ull c(ull a, ull b,)  
     ^