#include<bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using mint=modint998244353; //1000000007;
using ll=long long;
using pp=pair<int,int>;
#define sr string 
#define vc vector
#define db double
#define fi first
#define se second
#define rep(i,n) for(ll i=0;i<(ll)n;i++)
#define pb push_back
#define all(v) v.begin(),v.end()
#define pque priority_queue
#define bpc(a) __builtin_popcount(a)
int main(){
	ll n;cin>>n;
	//a*p+b/p*p;
	ll ans=0;
	rep(a,10)rep(b,10){
		if(!a&&!b)continue;
		ll ac=max(a,b),wa=n*10;
		while(wa-ac>1){
			ll p=(ac+wa)/2;
			if(n*(a*p+b)>p*p)ac=p;
			else wa=p;
		}
		ans+=ac-max(a,b);
	}
	cout<<ans;
}