# input import sys input = sys.stdin.readline II = lambda : int(input()) MI = lambda : map(int, input().split()) LI = lambda : [int(a) for a in input().split()] SI = lambda : input().rstrip() LLI = lambda n : [[int(a) for a in input().split()] for _ in range(n)] LSI = lambda n : [input().rstrip() for _ in range(n)] MI_1 = lambda : map(lambda x:int(x)-1, input().split()) LI_1 = lambda : [int(a)-1 for a in input().split()] def graph(n:int, m:int, dir:bool=False, index:int=-1) -> list[set[int]]: edge = [set() for i in range(n+1+index)] for _ in range(m): a,b = map(int, input().split()) a += index b += index edge[a].add(b) if not dir: edge[b].add(a) return edge def graph_w(n:int, m:int, dir:bool=False, index:int=-1) -> list[set[tuple]]: edge = [set() for i in range(n+1+index)] for _ in range(m): a,b,c = map(int, input().split()) a += index b += index edge[a].add((b,c)) if not dir: edge[b].add((a,c)) return edge mod = 998244353 inf = 1001001001001001001 ordalp = lambda s : ord(s)-65 if s.isupper() else ord(s)-97 ordallalp = lambda s : ord(s)-39 if s.isupper() else ord(s)-97 yes = lambda : print("Yes") no = lambda : print("No") yn = lambda flag : print("Yes" if flag else "No") def acc(a:list[int]): sa = [0]*(len(a)+1) for i in range(len(a)): sa[i+1] = a[i] + sa[i] return sa prinf = lambda ans : print(ans if ans < 1000001001001001001 else -1) alplow = "abcdefghijklmnopqrstuvwxyz" alpup = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" alpall = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" URDL = {'U':(-1,0), 'R':(0,1), 'D':(1,0), 'L':(0,-1)} DIR_4 = [[-1,0],[0,1],[1,0],[0,-1]] DIR_8 = [[-1,0],[-1,1],[0,1],[1,1],[1,0],[1,-1],[0,-1],[-1,-1]] DIR_BISHOP = [[-1,1],[1,1],[1,-1],[-1,-1]] prime60 = [2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59] sys.set_int_max_str_digits(0) # sys.setrecursionlimit(10**6) # import pypyjit # pypyjit.set_param('max_unroll_recursion=-1') from collections import defaultdict from heapq import heappop,heappush from bisect import bisect_left,bisect_right DD = defaultdict BSL = bisect_left BSR = bisect_right from math import isqrt n = II() print(isqrt(n))