def recurse(tree, id, min, max):
    if id >= len(tree):
        return True
    if tree[id] <= min or max <= tree[id]:
        return False
    return recurse(tree, id*2, min, tree[id]) and recurse(tree, id*2+1, tree[id], max)


if __name__ == '__main__':
    line = input().strip().split(',')
    tree = [0]
    for l in line:
        if l == 'None':
            continue
        tree.append(int(l))
    if recurse(tree, 1, (1 << 32) * -1, 1 << 32 - 1):
        print('True')
    else:
        print('False')