/in/foo.cc: In function 'int main()':
/in/foo.cc:30:6: error: invalid types 'int[int]' for array subscript
   b[j][1]=sum1%1000000007;
      ^
/in/foo.cc:38:6: error: invalid types 'int[int]' for array subscript
   b[j][2]=(a1*b1-sum1)%1000000007;
      ^