#include<bits/stdc++.h> //#include <atcoder/all> using namespace std; //using namespace atcoder; #define all(v) v.begin(),v.end() using ll = long long; using ull = unsigned long long; using lll = __int128; using vll=vector<ll>; using vvll = vector<vector<ll>>; using P = pair<ll,ll>; using vp=vector<pair<ll, ll>>; //using mint=modint1000000007; //using mint=modint998244353; const ll INF=1ll<<60; ll mod10=1e9+7; ll mod99=998244353; const double PI = acos(-1); #define rep(i,n) for (ll i=0;i<n;++i) #define per(i,n) for(ll i=n-1;i>=0;--i) #define rep2(i,a,n) for (ll i=a;i<n;++i) #define per2(i,a,n) for (ll i=a;i>=n;--i) template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return true; } return false; } template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return true; } return false; } bool solve(){ ll N;cin>>N; cout << (ll)sqrtl(N) << endl; return 0; } int main(){ cin.tie(0); ios::sync_with_stdio(false); ll T=1;//cin>>T; rep(i,T) solve(); }