def main():
    import sys
    input = sys.stdin.read().split()
    n = int(input[0])
    arr = list(map(int, input[1:]))
    
    current = arr
    for _ in range(n):
        m = len(current)
        if m < 3:
            break
        new = []
        for i in range(m - 2):
            a, b, c = current[i], current[i+1], current[i+2]
            if (a, b, c) in {(0,1,2), (1,2,0), (2,0,1)}:
                new.append(1)
            elif (a, b, c) in {(2,1,0), (1,0,2), (0,2,1)}:
                new.append(2)
            else:
                new.append(0)
        # Check if all new are zero
        if all(x == 0 for x in new):
            print(0)
            return
        current = new
    print(current[0])

if __name__ == '__main__':
    main()