n = int(input())

# Calculate the length L of the ushippoi number
L = 2 + (n - 1) // 36

# Determine the position within the group of length L
pos = (n - 1) % 36 + 1

remaining = pos
a = 1
b = 2

# Find the correct a and b for the given position
for a_candidate in range(1, 9):
    count = 9 - a_candidate
    if remaining <= count:
        b = a_candidate + remaining
        a = a_candidate
        break
    remaining -= count

# Construct the result string
result = str(a) + str(b) * (L - 1)

print(result)