N = int(input()) - 1
m = N // 36
N %= 36
ans = []
for a in range(1, 10):
    for b in range(a + 1, 10):
        s = [str(a), str(b)]
        ans.append(s)
v = ans[N]
v = v + [v[-1]] * m
print(*v, sep="")