A student has written a program to compute and output the sum of the squares of the first $n$ positive integers, $S_n={\sum }_{r=1}^n{r}^2$, for a user-entered positive integer $n$.

Figure 1 shows the student's program.

1  n = int(input("Enter a positive integer: "))
2  total_sum = 0
3  r = 1
4  while r < n:
5      total_sum = total_sum + r**2
6      r = r + 1
7  print(total_sum)

Describe how line 4 should be changed so that the program in Figure 1 works correctly.