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

bool psq(int x){
    int l=0,r=x,mid;
    while(l<=r){
        mid=(l+r)/2;
        if(mid*mid==x) return true;
        if(mid*mid<x) l=mid+1;
        else r=mid-1;
    }
    return false;
}

int nsq(int x){
    int l=0,r=x,mid,res=0;
    while(l<=r){
        mid=(l+r)/2;
        if(mid*mid<=x){
            res=mid;
            l=mid+1;
        } else r=mid-1;
    }
    return res;
}

signed main(){
    int x;cin>>x;
    int r=nsq(x);
    if(psq(x)) cout<<2*r-1<<endl;
    else cout<<2*r<<endl;
}