#include "bits/stdc++.h"
#include "atcoder/all"
 
using namespace std;
using namespace atcoder;
 
using lint=long long;
using ll=lint;
using namespace std;
#define endl "\n"
#define repp(i, m, n) for (int i = (int)m; i < (int)(n); i++)
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
lint mod=998244353;
#define vec vector
#define All(x) x.begin(),x.end()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define str string
lint inf64=1LL<<61;
int inf32=1<<30;

lint gcd(lint a, lint b){
	if(a<b)return gcd(b,a);
	if(a%b==0)return b;
	return gcd(b, a%b);
}

using namespace std;

using S=lint;
S op(S l, S r){
	return max(l,r);
}
S e(){
	return 0;
}

int main(){
	lint n;
	cin>>n;
	cout<<2*n-1;
}