import sys
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
INF = 2**63-1
mod = 998244353
S = []
for i in range(1, 10):
    for j in range(i + 1, 10):
        if i == j:
            continue
        S.append(10 * i + j)

S.sort()
n = ii()
n -= 1
p = n // len(S)
q = n % len(S)
ans = str(S[q]) + str(S[q] % 10) * (p)

print(ans)