m=10

def mat_mul(a, b) :
    I, J, K = len(a), len(b[0]), len(b)
    c = [[0] * J for _ in range(I)]
    for i in range(I) :
        for j in range(J) :
            for k in range(K) :
                c[i][j] += a[i][k] * b[k][j]
            c[i][j] %= m
    return c

def mat_pow(x, n):
    y = [[0] * len(x) for _ in range(len(x))]
    for i in range(len(x)):
        y[i][i] = 1
    while n > 0:
        if n & 1:
            y = mat_mul(x, y)
        x = mat_mul(x, x)
        n >>= 1
    return y

p,q,r,K=map(int,input().split())
ret = [[r], [q], [p]]
N=K-3
kmat=[[1,1,1],[1,0,0],[0,1,0]]
print(mat_mul(mat_pow(kmat,N),ret)[0][0])