N = int(input())
c = 0
nums = []
cnt = 0
N -= 1
c, N = divmod(N, 36)
nums = []
for a in range(1, 10):
    if 9-a <= N:
        N -= 9-a
    else:
        b = a + 1 + N
        print("".join(map(str, [a] + [b] * (c + 1))))
        break