#include<bits/stdc++.h>
using namespace std;
#define ll long long int

ll binpow(ll a, ll b, ll m) {
    a %= m;
    ll res = 1;
    while (b > 0) {
        if (b & 1)
            res = res * a % m;
        a = a * a % m;
        b >>= 1;
    }
    return res;
}

void solve(){
    ll n;
    cin>>n;
    ll num = sqrtll(n);
    if (num*num==n){
        cout<<2*num-1<<endl;
    }
    else{
        cout<<2*num<<endl;
    }
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    ll tt;
    tt =1;
    while(tt--){
        solve();
    }
    return 0;
}