If ${\text{a}}\;\;$ and ${\text{b}}\;$ are the roots of equation ${{\text{x}}^{\text{2}}}{\text{ + px + 1 = 0}}\;{\text{and}}\;{\text{c,}}$ d are the roots of equation $\;\;\;{{\text{x}}^{\text{2}}}{\text{ + qx + 1 = 0}}$, then the value of ${\text{E = }}\left( {{\text{a - c}}} \right)\left( {{\text{b - c}}} \right)\left( {{\text{a + d}}} \right)\left( {{\text{b + d}}} \right)$ is