View Compilation Error

0_0_28619407_7560.cpp: In constructor 'Mat::Mat(ll (*)[55])':
0_0_28619407_7560.cpp:30:17: error: 'n' was not declared in this scope
   for(int i=0;i<n;i++){
                 ^
0_0_28619407_7560.cpp: In member function 'Mat Mat::operator*(Mat&)':
0_0_28619407_7560.cpp:37:23: error: 'n' was not declared in this scope
         for(int i=0;i<n;i++){
                       ^
0_0_28619407_7560.cpp: In function 'Mat quickMod(Mat, ll)':
0_0_28619407_7560.cpp:48:19: error: 'n' was not declared in this scope
     for(int i=0;i<n;i++)ans.m[i][i]=1; 
                   ^
0_0_28619407_7560.cpp: In function 'int main()':
0_0_28619407_7560.cpp:63:3: error: 'n' was not declared in this scope
   n=x+2;
   ^