#include <bits/stdc++.h> using namespace std; int main() { string a, b, w; int x[100], y[100], k, n; cin >> N; for (int i = 1; i <= n; i++) { if (i <= 9) w = w + char(48 + i); else w = w + char(55 + i); } cin >> a >> b; while (a.length() < b.length()) a = '0' + a; while (b.length() < a.length()) b = '0' + b; a = '0' + a; b = '0' + b; for (int i = a.length() - 1; i >= 0; i--) { x[i] = w.find(a[i], 0); y[i] = w.find(b[i], 0); } for (int i = a.length() - 1; i >= 0; i--) { x[i] = x[i] + y[i]; if (x[i] >= n) { k = i; while (x[k] >= n) { x[k] = x[k] - N; x[k - 1]++; k--; } } } for (int i = a.length() - 1; i >= 0; i--) a[i] = w[x[i]]; while (a[0] == '0') a.erase(0, 1); cout << a << endl; return 0; }