n = int(input()) list1 = list(map(int, input().split())) a = list1[0] b = list1[1] c = list1[2] d = list1[3] if b - a == d - c: d1 = b - a print(a + d1*(n - 1)) if b / a == d / c: q = d / c print(int(a * q**(n - 1)))