solution_uit_55_180.cpp

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

set<int> prime;
ll mem[17][9 * 17 + 1][2];

bool isPrime(int n) {
    if (n < 2) return false;
    for (int i = 2; i * i <= n; i++) {
        if (n % i == 0) return false;
    }
    return true;
}

ll dp(string &s, int pos, int sum, bool lwr) {
    if (pos == (int) s.size()) return prime.count(sum);
    if (mem[pos][sum][lwr] != -1) return mem[pos][sum][lwr];
    ll ret = 0;
    for (int digit = 0; digit <= (lwr ? s[pos] - '0' : 9); digit++) {
        ret += dp(s, pos + 1, sum + digit, (lwr && digit == (s[pos] - '0')));
    }
    // cout << pos << ' ' << sum << ' ' << lwr << ' ' << ret << '\n';
    return mem[pos][sum][lwr] = ret;
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    for (int i = 2; i <= 9 * 17; i++) {
        if (isPrime(i)) prime.insert(i);
    }
    ll k;
    cin >> k;
    ll l = 2, r = 1e17, ans = -1;
    while (l <= r) {
        memset(mem, -1, sizeof(mem));
        ll m = (l + r) / 2;
        string s = to_string(m);
        if (dp(s, 0, 0, 1) >= k) {
            ans = m;
            r = m - 1;
        }
        else l = m + 1;
    }
    cout << ans << '\n';
}