from collections import defaultdict, Counter, deque
from itertools import groupby, accumulate, combinations, permutations, product, combinations_with_replacement
from bisect import bisect_left, bisect_right
from operator import itemgetter
import math

from string import ascii_lowercase
LMI=lambda:list(map(int, input().split()))
LMS=lambda:list(map(str, input().split()))
MI=lambda:map(int, input().split())
MS=lambda:map(str, input().split())
II=lambda:int(input())
IS=lambda:input().split()
LI=lambda:list(input())

N=II()
print(int(math.isqrt(N)))