#include<bits/stdc++.h>
using namespace std;
 
#define debug(x) cerr << #x << ": " << (x) << endl
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define dwn(i,a,b) for(int i=(a);i>=(b);i--)
#define pb push_back
#define all(x) (x).begin(), (x).end()
 
#define x first
#define y second
using pii = pair<int, int>;
using ll = long long;

#define int ll
 
inline void read(int &x){
    int s=0; x=1;
    char ch=getchar();
    while(ch<'0' || ch>'9') {if(ch=='-')x=-1;ch=getchar();}
    while(ch>='0' && ch<='9') s=(s<<3)+(s<<1)+ch-'0',ch=getchar();
    x*=s;
}

signed main(){
	int n; cin>>n;
	int l=sqrt(n/2);
	int r=ceil(sqrt(n));
	l=max(l, 1LL);
	r=max(r, 1LL);
	int res=1e18;
	rep(b, l, r){
		int a=(n+b-1)/b;
		if(a>=b && a<=b*2 && a*b>=n) res=min(res, a*b-n);
	}
	cout<<res<<endl;
	return 0;
}