#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

int main() {
    set<string> se;
    ll n;
    cin >> n;

    srep(i,1,n+1){
        ll ii = i;
        if(ii * ii > n)break;
        ll jj = n / ii;
        string s = to_string(ii) + to_string(jj);
        se.insert(s);
        s = to_string(jj) + to_string(ii);
        se.insert(s);
    }

    int ans = se.size();

    cout << ans << endl;
    return 0;
}