c#include <bits/stdc++.h> using namespace std; int main(){ cin.tie(NULL); cout.tie(NULL); ios_base::sync_with_stdio(false); int N; cin >> N; int ans = 0; for(int i = 1; i <= N; i *= 10){ ans += N - i + 1; } cout << ans << "\n"; return 0; }
#include <bits/stdc++.h> using namespace std; int main(){ cin.tie(NULL); cout.tie(NULL); ios_base::sync_with_stdio(false); int N; cin >> N; int ans = 0; for(int i = 1; i <= N; i *= 10){ ans += N - i + 1; } cout << ans << "\n"; return 0; }