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

using namespace std;

// 符号转化为数字
int get_num(char c) {
    if (isdigit(c)) {
        return c - '0';
    }
    if ('a' <= c && c <= 'z') {
        return c - 'a' + 10;
    }
    if ('A' <= c && c <= 'Z') {
        return c - 'A' + 10;
    }
    return 0;
}

// 数字转化为符号
char get_char(int num) {
    return '0';
}

//将字符串根据进制转化为数字
int to_num(string& number, int base) {
    int n = number.size();
    long long num = 0;
    for (int i = 0; i < n; i++) {
        char ch = number[i];
        num *= base;
        num += get_num(ch);
    }
    return num;
}


//将数字根据进制转化为字符串
string tostring(int num, int base) {
    if (num == 0) return "0";

    string ans;
    while (num > 0) {
        ans += get_char(num % base);
        num /= base;
    }
    reverse(ans.begin(), ans.end());
    return ans;
}

string convertBase(string& num, int st_base, int en_base) {
    return tostring(to_num(num, st_base), en_base);
}

int main() {
    string number;
    int st_base, en_base;

    cout << "输入数字：";
    cin >> number;
    cout << "输入源进制（2-16）：";
    cin >> st_base;
    cout << "输入目标进制（2-16）：";
    cin >> en_base;

    string ans = convertBase(number, st_base, en_base);
    cout << "转换后的数字是：" << ans << endl;

    return 0;
}