def solve(testcase):
    n = II()
    A = LII()

    while len(A) > 1:
        B = []
        for i in range(1, len(A)):
            B.append(abs(A[i] - A[i - 1]))
        A = B
    
    print(A[0])

for testcase in range(1):
    solve(testcase)