View Compilation Error

0_0_17791206_20634.cpp:28:1: error: 'LL' does not name a type
 LL inv(long long a,long long m)
 ^
0_0_17791206_20634.cpp: In function 'int Gauss(int, int)':
0_0_17791206_20634.cpp:128:33: error: 'inv' was not declared in this scope
         x[i]=(temp*inv(a[i][i],3))%3;
                                 ^