#include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; long long MOD = 1000000007; int main() { long long N; cin >> N; string ans; long long x = 0; int i; for ( i = 1; i <= 9; i++ ) { long long a = 1; for ( int j = i; j > 0; j-- ) { a *= 26; } if ( a > N ) { break; } N -= a; } for ( ; i > 0; i-- ) { ans += 'A' + N%26; N /= 26; } reverse( ans.begin(), ans.end() ); cout << ans << endl; return 0; }