#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("YES");}else{puts("NO");}
#define MAX_N 200005

int main() {
    ll n;
    cin >> n;
    ll l = 1, r = 1001001001;
    while(l+1<r){
        ll m = (l+r)/2;
        if(m*m>n) r = m;
        else l = m;
    }
    ll ans = l+n/(l+1);
    cout << ans << endl;
    return 0;
}