#include<bits/stdc++.h>
using namespace std;
/*#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
/*template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
*/typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll,ll> pl;
typedef pair<int,int> pii;

#define int ll
#define LOCAL 0
#define dbg(x) cout << #x << " is " << x << "\n"
#define gll(x) scanf("%d",&x)
#define gll2(x,y) scanf("%d%d",&x,&y)
#define gll3(x,y,z) scanf("%d%d%d",&x,&y,&z)
#define gllarr(arr,n) f(i,n) gll(arr[i]);
#define sz(x) ((int)x.size())
#define s(x) sort(x.begin(),x.end())
#define all(v) v.begin(),v.end()
#define rs(v) { s(v) ; r(v) ; }
#define r(v) {reverse(all(v));}
#define pb push_back
#define f(i,n) for(int i=0;i<n;i++)
#define fr(i,n) for(int i=n-1;i>=0;i--)
#define rep(i,a,b) for(int i=a;i<=b;i++)
#define repr(i,a,b) for(int i=a;i>=b;i--)

const ll mod = (ll)1e9 + 7;
const ll inf = (ll)1e16;
const ld eps = 1e-12;
const ll N = (int)1e5 + 5;
const ll LOGN = 19;
const ld PI = 3.14159265358979323846;
inline ll mul(ll a, ll b, ll m = mod) { return (ll)(a * b) % m;}
inline ll add(ll a, ll b, ll m = mod) { a += b; if(a >= m) a -= m; if(a < 0) a += m; return a;}
inline ll power(ll a, ll b, ll m = mod) { if(b == 0) return 1; if(b == 1) return (a % m); ll x = power(a, b / 2, m); x = mul(x, x, m); if(b % 2) x = mul(x, a, m); return x;}

int len, n;
string first_part, second_part;

bool Check(int mid) {
    int will = mid - 1;
    string app = to_string(will);
    r(app);
    while(app.size() < len - 2) app.pb('0');
    r(app);
    string cand = first_part + app + second_part;
    int num = stoi(cand);
    return (num <= n);
}

bool CheckFirst() {
    string zeros;
    while(zeros.size() < len - 2) zeros.pb('0');
    string cand = first_part + zeros + second_part;
    int num = stoi(cand);
    return (num <= n);
}

bool CheckLast() {
    string zeros;
    while(zeros.size() < len - 2) zeros.pb('9');
    string cand = first_part + zeros + second_part;
    int num = stoi(cand);
    return (num <= n);
}

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    if (LOCAL) {
        freopen("C:\\Users\\Dishant\\Desktop\\Collection-DEV c++\\input.txt", "r", stdin);
        freopen("C:\\Users\\Dishant\\Desktop\\Collection-DEV c++\\output.txt", "w", stdout);
    }
    cin>>n;
    int ans = 0;
    for(int i = 1; i <= n; i++) {
        string curr = to_string(i);
        char ff = curr[0], ss = curr.back();
        //cout<<i<<' '<<ff<<' '<<ss<<endl;
        if(ss == '0') continue;
        if(ff == ss) ans++;
        first_part.clear();
        second_part.clear();
        first_part += ss;
        second_part += ff;
        string st = first_part + second_part;
        string temp;
        int check = stoi(st);
        if(check <= n) ans++;
        else continue;
        for(len = 3; len <= 6; len++) {
            int low = 1, high = power(10, len - 2);
            int to = 0;
            if(!CheckFirst()) {
                continue;
            }
            if(CheckLast()) {
                ans += high;
                continue;
            }
            while(low <= high) {
                int mid = (low + high) >> 1;
                if(Check(mid)) {
                    to = mid;
                    low = mid + 1;
                }
                else high = mid - 1;
            }
            ans += to;
        }
    }
    cout<<ans<<endl;
    return 0;
}


Measured memory_bytes: 256