Let $A = \sum _ { i = 1 } ^ { 10 } \sum _ { j = 1 } ^ { 10 } \min \{ i , j \}$ and $B = \sum _ { i = 1 } ^ { 10 } \sum _ { j = 1 } ^ { 10 } \max \{ i , j \}$. Then $A + B$ is equal to $\_\_\_\_$.