#include<bits/stdc++.h>
using namespace std;
bool perfectsqr(int n) {
    int root = sqrt(n);
    return root * root == n;
}

int nearestsqr(int n){
    int ans = (int)(floor(sqrt(n)));
    return ans;
}
int main(){
    int n; cin>>n;
    int ans = nearestsqr(n);
    if(perfectsqr(n)){
        cout<< 2 * ans - 1<<endl;
    }
    else {
        cout<< 2*ans  <<endl;
    }
}