#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
//-------------------------------------------------------

int N;
set<ll> P[1300];
ll ret[1300];

set<ll> enumpr(ll n) {
	set<ll> V;
	for(ll i=2;i*i<=n;i++) while(n%i==0) V.insert(i),n/=i;
	if(n>1) V.insert(n);
	return V;
}

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	for(j=2;j<=1262;j++) P[j]=enumpr(j);
	
	for(j=2;j<=1262;j++) {
		set<ll> did;
		for(i=j;i>=2;i--) {
			auto S=enumpr(i);
			int ng=0;
			FORR(s,S) ng+=did.count(s);
			if(ng==0) {
				FORR(s,S) did.insert(s);
				ret[j]+=i;
			}
		}
		ret[j]=max(ret[j],ret[j-1]);
	}
	cin>>N;
	
	cout<<ret[N]<<endl;
	
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}