#include <bits/stdc++.h>
using namespace std;

#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
#define rep3(i,m,n) for(int (i)=m;(i)<=(n);(i)++)
#define rep3rev(i,m,n) for(int (i)=m;(i)>=(n);(i)--)
#define all(a) (a.begin()),(a.end())
#define rall(a) (a.rbegin()),(a.rend())
#define fi first
#define se second
#define pb push_back
#define eb emplace_back

using ll = long long;
using vll = vector<ll>;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using P = pair<int, int>;
using LD = long double;

template <typename T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template <typename T> bool chmin(T &a, const T &b) { if (a > b) { a = b; return true; } return false; }
template <typename T> void coutall(T v) { if(v.empty()){cout << endl; return;} for(auto i = v.begin(); i != --v.end(); i++){cout << *i << " ";} cout << *--v.end() << endl; }
template <typename T> void DEBUGall(T v) { if(v.empty()){cerr << endl; return;} for(auto i = v.begin(); i != --v.end(); i++){cerr << *i << " ";} cerr << *--v.end() << endl; }
inline void IN(void){ return; }
template <typename First, typename... Rest> void IN(First& first, Rest&... rest){ cin >> first; IN(rest...); return; }
inline void OUT(void){ cout << "\n"; return; }
template <typename First, typename... Rest> void OUT(First first, Rest... rest){ cout << first << " "; OUT(rest...); return; }
inline void DEBUG(void){ cerr << "\n"; return; }
template <typename First, typename... Rest> void DEBUG(First first, Rest... rest){ cerr << first << " "; DEBUG(rest...); return; }

void yes(bool ok = true){ cout << (ok ? "yes" : "no") << endl; }
void Yes(bool ok = true){ cout << (ok ? "Yes" : "No") << endl; }
void YES(bool ok = true){ cout << (ok ? "YES" : "NO") << endl; }
ll myceil(ll a, ll b) { return a >= 0 ? (a+b-1)/b : -((-a)/b); }
ll myfloor(ll a, ll b) { return a >= 0 ? a/b : -myceil(-a, b); }

void Main(){
    string s1 = "01689", s2 = "01986";
    string s; IN(s);
    for(char& c : s){
        if(c == '6') c = '9';
        else if(c == '9') c = '6';
    }
    reverse(all(s));
    OUT(s);
    return;
}

int main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(15);
    Main();
    return 0;
}
#include <bits/stdc++.h>

// 1. dp
typedef long double ld;
#define int long long

#define gcd            __gcd
#define endl           "\n"
#define setbits(x)     __builtin_popcountll(x)
#define zrobits(x)     __builtin_ctzll(x)
#define mod            1000000007
#define mod2           998244353
#define maxe           *max_element
#define mine           *min_element
#define inf            1e18
#define pb             push_back
#define all(x)         x.begin(), x.end()
#define f              first
#define s              second
#define lb             lower_bound
#define ub             upper_bound
#define ins            insert
#define sz(x)          (int)(x).size()
#define mk             make_pair
#define deci(x, y)     fixed<<setprecision(y)<<x
#define w(t)           int t; cin>>t; while(t--)
#define nitin          ios_base::sync_with_stdio(false); cin.tie(nullptr)
#define PI             3.141592653589793238
using namespace std;

void solve() {
    int n,k;
    cin>>n>>k;
    map<int,int>m;
    for(int i=1;i<=2*n;i++){
        if(i<=(n+1))
        m[i]=i-1;
        else{
            m[i]=2*n-i+1;
        }
    }
    int ans=0;
    for(int i=1;i<=2*n;i++){
        if(i>=k)
        ans+=(m[i]*(m[i-k]));
    }
    cout<<ans<<endl;
}

int32_t main() {
    nitin;

    solve();
}
