洛谷P1143

#include<iostream>
#include<cmath>
#include<stack>
using namespace std;
int toto(char i) {
	if (i >= 'A') return i - 'A' + 10;

	if (i >= '0') return i - '0';
}
char outout(int i) {
	if (i > 9) return i - 10 + 'A';

	return i + '0';
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	stack <char>sk;
	int to, as;
	string st;
	long long a = 0;
	double from;
	cin >> from >> st;
	as = st.size();

	for (int i = 0; i < as; i++) a += (as - i - 1 ? pow(from, as - i - 1) : 1) * toto(st[i]);

	cin >> to;

	while (a) {
		sk.push(outout(a % to));
		a /= to;
	}

	while (!sk.empty()) {
		cout << sk.top();
		sk.pop();
	}

	return 0;
}