#include <iostream>
using namespace std;
long long n, ans, x, a[1000000];
int main() {
	cin >> n;
	ans = ++ n;
	for (long long i = ans; i > 0; i /= 26) {
		if (i % 26 == 0) {
			a[x++] = 26;
			-- i;
			continue;
		}
		a[x++] = i % 26;
	}
	for (int i = x - 1; i > -1; -- i) {
		if(a[i] <= 25) cout << char('A' + a[i] - 1);
		else cout << 'Z';
	}
	cout << endl;
	return 0;
}