vector<vector<int>> transpose(vector<vector<int>>& A) {

         int C = A.size() ;

         int R = A[].size() ;

         vector<vector<int>> result(R,vector<int>(C) ) ;

         for( int i =  ; i < A.size() ; i++ )

             for( int j = ; j < A[].size();j++ )

             {

                 result[j][i] = A[i][j];

             }

         return result;

     }