D = int(input())

C = [0] * 101

def keta(n):
    c = 1
    while 10 ** c <= n:
        c += 1
    return c
start = 1
now = 1
while start <= 100:
    k = keta(now)
    memo = now
    for i in range(k):
        C[start] = now // (10 ** (k - 1 - i))
        start += 1
        now = now % (10 ** (k - 1 - i))
        if start > 100:break
    now = memo + 1
print(C[D])