View Compilation Error

0_0_28353067_15808.cpp: In function 'int TrA()':
0_0_28353067_15808.cpp:11:16: error: 'n' was not declared in this scope
  for(int i=0;i<n;i++)
                ^
0_0_28353067_15808.cpp: In function 'node mul(node, node)':
0_0_28353067_15808.cpp:22:16: error: 'n' was not declared in this scope
  for(int i=0;i<n;i++)
                ^
0_0_28353067_15808.cpp: In function 'int main()':
0_0_28353067_15808.cpp:50:17: error: 'n' was not declared in this scope
   scanf("%d%d",&n,&k);
                 ^