7) The graphic symbols in the grid “$\diamond$, “$\bigcirc$, “$\nabla$”, “公” represent numbers to be filled in the grid, with the same symbols indicating the same numbers. As shown in the figure. If the sums of the numbers in the first column, the third column, the second row, and the fourth row are $36, 50, 41, 37$ respectively, then the sum of the four numbers in the third row is $\qquad$.


7) 33.