atcoder - 152 D - Handstand 2

/*
https://atcoder.jp/contests/abc152/tasks/abc152_d
*/

#include <bits/stdc++.h>
using namespace std;
 
#define pb push_back
 
 
int solve() {
    
    int n;
    cin>>n;
    int cnt[10][10]={};
    for(int i=1;i<=n;i++){
        int x = (to_string(i)[0]-'0');
        int y = i%10;
        ++cnt[x][y];
    }
 
    int s=0;
    for(int i=0;i<10;i++){
        for(int j=0;j<10;j++){
            s+=cnt[i][j]*cnt[j][i];
        }
    }
    cout<<s<<endl;
 
}
 
 
int main()
{
    int test = 1, tc = 0;
    //scanf("%d", &test);
   // (void)getchar();
    //cin >> test;
    while (test--) {
        //printf("Case %d: ", ++tc);
        solve();
    }
    return 0;
}