p, q, r, K = map(int, input().split())

def matrix(a, b):
    ans = [[0]*len(b[0]) for _ in range(len(a))]
    for i in range(len(a)):
        for j in range(len(b[0])):
            ans[i][j] = sum(a[i][k]*b[k][j] for k in range(len(b)))%10
    return ans

dp = [[[0]*3 for _ in range(3)]]
for i in range(3):
    dp[0][0][i] = 1
dp[0][1][0] = 1
dp[0][2][1] = 1
for _ in range(59):
    dp.append(matrix(dp[-1], dp[-1]))

K -= 3
ansM = [[r], [q], [p]]
for i in range(60):
    if 1<<i & K:
        ansM = matrix(dp[i], ansM)

print(ansM[0][0])