/*
TASK:minitime
LANG:C++
*/
#include<iostream>
using namespace std;
int main()
{
    int n,vr,minvr=1000,i;
    cin>>n;
    if(n==3){cout<<"3\n";return 0;}
    for(i=2;i<n;i++){vr=0;
                     vr=i+n/i;
                     if(!n%i==0)vr++;
                     if(vr<minvr)minvr=vr;
                     }
    if(minvr==1000)cout<<n<<"\n";
    else cout<<minvr<<"\n";
    return 0;
}                 
    
