#include <string>
int count_digit(int n, char d) {
    int cnt = 0;
    std::string s = std::to_string(n);
    for (int i = 0; i < s.length(); i++)
        if (s[i] == d)
            cnt++;
    return cnt;
}
int sum_digit(int n, char d) {
    int sum = 0;
    for (int i = 1; i <= n; i++)
        sum += count_digit(i, d);
    return sum;
}