By Matlab please

In a one-dimensional random walk, the position x of a walker is computed by: x_ = x_ + s where s is a random number. Write a program that calculates the number of steps required for the walker to reach a boundary x = plusminus B. Use MATLAB's built-in function randn (1, 1) to calculate s. Run the program 100 times (by using a loop) and calculate the average number of steps when B = 10