If \(\rm\overrightarrow{a}\) = 2î − 3ĵ − k̂, \(\rm\overrightarrow{b}\) = −î + k̂, \(\rm\overrightarrow{c}\) = 2ĵ − k̂, then the area of parallelogram, whose diagonals are \((\rm\overrightarrow{a}+\overrightarrow{b})\) and \((\rm\overrightarrow{b}+\overrightarrow{c})\) is ________