def Neighbours(ls):
    visited = set()
    illegal = set()
    count = 0
    for i in range(len(ls)-1, -1,-1):
        if ls[i] == 1:
            count += 1
        else:
            break
    for i in range(len(ls)-count): 
        if ls[i] not in illegal:   
            for j in range(1, 5):
                if ls[i] != j and j not in illegal:     
                    temp = ls.copy()
                    temp[i] = j
                    visited.add(tuple(temp))
        illegal.add(ls[i])
    return list(visited)