#include <bits/stdc++.h>
using namespace std;
using ll = long long;
//#include <atcoder/modint>
//using namespace atcoder;
//using mint = modint998244353;
# define M_PI           3.14159265358979323846  /* pi */
#define watch(x) cout << (#x) << " is " << (x) << endl
 
//#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
 
//const int MOD = (1e9+7);
template < typename T = int > ostream& operator << (ostream &out, const vector < T > &v){ 
    for (const T &x: v) out << x << ' '; 
    return out;
}
void printmat(const vector<vector<int>>& mat) {
    for (auto row : mat) {
        for (auto elem : row)
            cout << elem << " ";
        cout << "\n";
    }
}
void printdq(const deque<int>& v) {
    for (auto elem : v)
        cout << elem << " ";
    cout << endl;
}
void printv(const vector<int>& v) {
    for (auto elem : v)
        cout << elem << " ";
    cout << "\n";
}
void printvll(const vector<ll>& v) {
    for (auto elem : v)
        cout << elem << " ";
    cout << endl;
}
void printd(const deque<int>& v) {
    for (auto elem : v)
        cout << elem << " ";
    cout << endl;
}
void printvp(const vector<pair<int,int>>& vp) {
    for (auto pr : vp) {
        cout << pr.first << " " << pr.second;
        cout << "\n";
    }
}
void printvs(const vector<set<int>>& vs) {
    for (auto row : vs) {
        for (auto elem : row)
            cout << elem << ", ";
        cout << endl;
    }
}
void printht(const unordered_map<int, int>& ht) {
    for (auto elem : ht)
        cout << elem.first << " : " << elem.second << endl;
}
void printmp(const map<int, int>& ht) {
    for (auto elem : ht)
        cout << elem.first << " : " << elem.second << endl;
}
void printst(const set<int>& st) {
    for (auto elem : st)
        cout << elem << " ";
    cout << endl;
}
 
bool isPrime(long long n) {
    if (n <= 1)
        return false;
    if (n <= 3)
        return true;
    if (n % 2 == 0 || n % 3 == 0)
        return false;
    for (long long i = 5; i * i <= n; i = i + 6)
        if (n % i == 0 || n % (i + 2) == 0)
            return false;
    return true;
}
 
map<long long, long long> primeFactors(long long n) {
    map<long long, long long> ans;
    while (n % 2 == 0) {
        ans[2]++;
        n = n/2;
    }
    for (long long i = 3; i*i <= (n); i = i + 2) {
        while (n % i == 0) {
            ans[i]++;
            n = n/i;
        }
    }
    if (n > 2)
        ans[n]++;
    return ans;
}
 
int find_f(const vector<int>& uf, int i) {
    while (uf[i]!=i)
        i = uf[i];
    return i;
}
bool union_f(vector<int>& uf, vector<int>& sz, int a, int b) {
    a = find_f(uf, a);
    b = find_f(uf, b);
    //cout << "a, b = " << a << ", " << b << endl;
    if (a==b) return false;
    if (sz[a] < sz[b]) {
        //cout << "sz[a], sz[b] = " << sz[a] << ", " << sz[b] << endl;
        //cout << "a, b = " << a << ", " << b << endl;
        swap(a,b);
        //cout << "a, b = " << a << ", " << b << endl;
    }
    sz[a] += sz[b];
    uf[b] = a;
    return true;
}
 
long long modexp(long long b, long long e, long long M) {
    if (!e) return 1;
    b %= M;
    long long x = modexp(b * b % M, e / 2, M);
    if (e % 2) {
        return b * x % M;
    } else {
        return x;
    }
}


ll gcdExtended(ll a, ll b, ll* x, ll* y) {
    if (a == 0) {
        *x = 0, *y = 1;
        return b;
    }
    ll x1, y1;
    ll gcd = gcdExtended(b % a, a, &x1, &y1);
    *x = y1 - (b / a) * x1;
    *y = x1;
    return gcd;
}

ll modInverse(ll a, ll m) {
    ll x, y, res=-1;
    ll g = gcdExtended(a, m, &x, &y);
    if (g != 1) {
        //cout << "Inverse doesn't exist";
        res = -1;
    } else {
        // m is added to handle negative x
        res = (x % m + m) % m;
    }
    return res;
}

int lenOfLIS(vector<int>& v) {        
    int n = v.size(), len = 0;
    vector<int> dp(n,0);
    for (int num : v) {
        int i = lower_bound(dp.begin(), dp.begin()+len, num) - dp.begin();
        dp[i] = num;
        if (i == len) {
            len++;
        }
    }
    return len;        
}

const int MOD = 1e9 + 7;
struct mi {
 	int v; explicit operator int() const { return v; }
	mi() { v = 0; }
	mi(long long _v) : v(_v % MOD) { v += (v < 0) * MOD; }
};
mi& operator+=(mi& a, mi b) { 
	if ((a.v += b.v) >= MOD) a.v -= MOD; 
	return a;
}
mi& operator-=(mi& a, mi b) { 
	if ((a.v -= b.v) < 0) a.v += MOD; 
	return a;
}
mi operator+(mi a, mi b) { return a += b; }
mi operator-(mi a, mi b) { return a -= b; }
mi operator*(mi a, mi b) { return mi((long long) a.v * b.v); }
mi& operator*=(mi& a, mi b) { return a = a * b; }
mi pow(mi a, long long p) {
	assert(p >= 0);
	return p == 0 ? 1 : pow(a * a, p / 2) * (p & 1 ? a : 1);
}
mi inv(mi a) { assert(a.v != 0); return pow(a, MOD - 2); }
mi operator/(mi a, mi b) { return a * inv(b); }


int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);    
    int T=1, caseIdx=0;
    //cin >> T;  
    while (T--) {
        //caseIdx++; 
        ll b;
        cin >> b;
        ll ans = 2*b-1;
        
        //cout << fixed << setprecision(9);
        cout << ans << "\n";
        //cout << "Case #" << caseIdx << ": " << ans << "\n";   
    }
}