View Compilation Error

0_0_35871286_23861.cpp: In function 'mat mat_mul(mat, mat)':
0_0_35871286_23861.cpp:17:55: error: 'mod' was not declared in this scope
         res.a[i][j]=(res.a[i][j]+x.a[i][k]*y.a[k][j])%mod;  
                                                       ^
0_0_35871286_23861.cpp: In function 'void mat_pow(long long int)':
0_0_35871286_23861.cpp:23:14: error: 'mem' was not declared in this scope
     mem(c.a,0);
              ^
0_0_35871286_23861.cpp:33:36: error: 'mod' was not declared in this scope
     printf("%lld\n",(res.a[0][0]*3%mod+res.a[0][1]*2%mod+res.a[0][2])%mod);
                                    ^