#include <bits/stdc++.h>
#define DB double
#define LL long long

#define MST(a, b) memset((a), (b), sizeof(a))
#define MRK() cout << "Mark" << endl;
#define WRT(x) cout << #x << " = " << (x) << endl;

#define MAXN 210000
#define MAXM 410000
#define MOD 998244353
#define INF 0x3f3f3f3f
#define LLINF 0x3f3f3f3f3f3f3f3f
#define EPS 1e-5

#define _ 0
using namespace std;

int getbitsum(int x) {
    int sum = 0;
    while (x) {
        sum += x % 10;
        x /= 10;
    }
    return sum;
}
int sum[MAXN];
int buc[80];

int main() {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) sum[i] = getbitsum(i);
    int ans = 0;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++) ans += (sum[i] == sum[j]);
    cout << ans;
    return ~~(0 ^ _ ^ 0);
}