N = int(input())
ans = [-1]
for i in range(1, N + 1):
    for v in range(1, 10):
        if v == ans[-1]:
            continue
        flag = 1
        for a in range(1, i):
            b = i - a
            if b <= a:
                break
            if ans[a] == ans[b]:
                if v <= ans[a]:
                    flag = 0
        if flag:
            ans.append(v)
            break

ans.pop(0)
print(*ans, sep="")