p, q, r, k = map(int, input().split()) t = [[0] * 1000 for _ in range(64)] for j in range(1000): t[0][j] = (j % 10 + j // 10 % 10 + j // 100) % 10 + j * 10 % 1000 for i in range(63): for j in range(1000): t[i + 1][j] = t[i][t[i][j]] k -= 3 p %= 10 q %= 10 r %= 10 x = p * 100 + q * 10 + r for i in range(64): if (k >> i) & 1: x = t[i][x] print(x % 10)