#include<bits/stdc++.h>

using namespace std;

#pragma GCC optimize ("O3")

typedef long long ll;
typedef unsigned int ull;
typedef long double lld;

#define int long long

/*---------------------------------------------------------------------------------------------------------------------------------------------*/
#ifdef ONLINE_JUDGE
#define debug(x)
#else
#define debug(x) cerr << #x <<" "; _print(x); cerr << endl;
#endif

#define int long long
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update> 
#define fastio() ios_base::sync_with_stdio(false);cin.tie(NULL)
#define endl "\n"
#define all(x) (x).begin(), (x).end()
#define INF 1e18
#define nline "\n"
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define ff first
#define ss second
#define PI 3.141592653589793238462
#define yes cout << "YES\n"
#define no cout << "NO\n"
#define setbits(x)  __builtin_popcountll(x)

#define MOD 1000000007

void _print(ll t) {cerr << t;}
void _print(string t) {cerr << t;}
void _print(char t) {cerr << t;}
void _print(lld t) {cerr << t;}
void _print(double t) {cerr << t;}
void _print(ull t) {cerr << t;}

template <class T, class V> void _print(pair <T, V> p);
template <class T> void _print(vector <T> v);
template <class T> void _print(set <T> v);
template <class T, class V> void _print(map <T, V> v);
template <class T> void _print(multiset <T> v);
template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.ff); cerr << ","; _print(p.ss); cerr << "}";}
template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}

int ceilCustom(int a, int b) {
    return (a + b - 1) / b;
}

vector<int> vinput(int n) {
    vector<int> v(n);
    for (int i = 0; i < n; i++) {
        cin >> v[i];
    }
    return v;
}

/*---------------------------------------------------------------------------------------------------------------------------------------------*/

void solve(){
    int n;
    cin >> n;
    int x = sqrtl(n);
    int ans = x;
    if (x*(x+1) <= n) {
      ans += x;
    }
    else if (x*(x-1) <= n) {
      ans += x-1;
    }
    cout << ans << '\n';
}

signed main(){
    
    fastio();

    int t = 1; 
    // cin >> t;
    while(t--){
        solve();
    }

    return 0;
}