N = int(input())
L = []
for i in range(12,100):
    s = str(i)
    if int(s[0]) < int(s[1]):
        L.append(i)

le = len(L)
y = N//le
if N % le == 0:
    print(str(L[-1])+str(L[-1]%10)*(y-1))
else:
    x = L[N%le-1]
    print(str(x)+str(x%10)*y)