import sys
input = sys.stdin.readline
p, q, r, K = map(int, input().split())

def ArrayMultiple(a, b, mod):
  n = len(a)
  m = len(b[0])
  c = [[0] * n for _ in range(n)]
  for i in range(n):
    for j in range(m):
      for k in range(n):
        c[i][j] += a[i][k] * b[k][j]
        c[i][j] %= mod
  return c

def ArrayPower(a, k, mod):
  bn = list(bin(k)[2: ])
  ln = len(bn)
  n = len(a)
  bn.reverse()
  res = [[int(i == x) for i in range(n)] for x in range(n)]
  for i in range(ln):
    if int(bn[i]):
      res = ArrayMultiple(res, a, mod)
    a = ArrayMultiple(a, a, mod)
  return res

a = [[1, 1, 1], [1, 0, 0], [0, 1, 0]]
ak = ArrayPower(a, K - 3, 10)[0]
print((ak[0] * r + ak[1] * q + ak[2] * p) % 10)