AC

#include <iostream>
#include <string>
#include <algorithm>

bool hasUniqueDigits(const std::string& num) {
    std::string sortedNum = num;
    std::sort(sortedNum.begin(), sortedNum.end());
    for (size_t i = 1; i < sortedNum.size(); ++i) {
        if (sortedNum[i] == sortedNum[i - 1]) {
            return false;
        }
    }
    return true;
}

int main() {
    for (int a = 123; a <= 333; ++a) {
        int b = 3 * a;
        int c = 5 * a;

        std::string strA = std::to_string(a);
        std::string strB = std::to_string(b);
        std::string strC = std::to_string(c);

        if (strA.length() == 3 && strB.length() == 3 && strC.length() == 3) {
            std::string combined = strA + strB + strC;
            if (combined.length() == 9 && hasUniqueDigits(combined)) {
                std::cout << b << std::endl;
                return 0;
            }
        }
    }

    std::cout << "No solution found" << std::endl;
    return 0;
}