#include <bits/stdc++.h> using namespace std; #define rep(i, n) for(int i = 0; i< (int)(n); i++) using ll = long long; using ull = unsigned long long; using vi = vector<int>; ll INF = 2e18; #define Yes cout << "Yes" << endl #define No cout << "No" << endl #define YN {cout<<"Yes"<<endl;}else{cout<<"No"<<endl;} // true → Yes false → No // cout << fixed << setprecision(20); int main() { int N; cin>>N; int i = 1; while(true) { if(i*i >= N) { cout << i-1 << endl; return 0; } else i++; } }