def mat_mul(x,y)
  len_x = x.size
  len_y = y[0].size
  num = y.size
  ret = Array.new(len_x){Array.new(len_y,0)}
  len_x.times do |i|
    len_y.times do |j|
      num.times do |k|
        ret[i][j] += x[i][k] * y[k][j]
        ret[i][j] %= 10
      end
    end
  end
  ret
end

def mat_pow(x,n)
  size = x.size
  ret = Array.new(size){Array.new(size,0)}
  size.times do |i|
    ret[i][i] = 1
  end
  while n > 0
    if n&1 == 1
      ret = mat_mul(ret,x)
    end
    x = mat_mul(x,x)
    n >>= 1
  end
  ret
end

p,q,r,k = gets.chomp.split(" ").map(&:to_i)
k -= 3
mat = [[1,1,1],[1,0,0],[0,1,0]]
mat = mat_pow(mat,k)
ans = mat_mul(mat,[[r],[q],[p]])
puts ans[0][0]