def dfs():
    if sum(X) == 2:
        if 2 in X:
            return True
        else:
            return False
    for i in range(7):
        for j in range(3):
            if X[i + j] == 0:
                break
        else:
            for j in range(3):
                X[i + j] -= 1
            if dfs():
                return True
            for j in range(3):
                X[i + j] += 1
    for i in range(9):
        if X[i] == 3:
            X[i] -= 3
            if dfs():
                return True
            X[i] += 3
    return False

S = input()
Y = [0] * 9
for s in S:
    Y[int(s) - 1] += 1

ans = []
for i in range(9):
    if Y[i] == 4:
        continue
    X = Y[:]
    X[i] += 1
    for j in range(9):
        if X[j] == 0 or X[j] == 2:
            continue
        else:
            break
    else:
        print(i + 1)
        exit()
    if dfs():
        print(i + 1)