import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        long N = scan.nextLong();
        c(N);
    }
    public void c(long N) {
        StringBuilder sb = new StringBuilder();
        while(0 < N) {
            N -= 1;
            int mod = (int) (N % 26);
            sb.append((char)(mod + (int)'a'));
            N /= 26;
        }
        System.out.println(sb.reverse().toString());
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.HashMap; HashMap java.util import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        long N = scan.nextLong();
        c(N);
    }
    public void c(long N) {
        StringBuilder sb = new StringBuilder();
        while(0 < N) {
            N -= 1;
            int mod = (int) (N % 26);
            sb.append((char)(mod + (int)'a'));
            N /= 26;
        }
        System.out.println(sb.reverse().toString());
    }
} Main public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    } main {
        Main main = new Main();
        main.solve();
    } Main main = new Main(); main new Main() main.solve() main.solve main String[] args args public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        long N = scan.nextLong();
        c(N);
    } solve {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        long N = scan.nextLong();
        c(N);
    } Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in))); scan new Scanner(new BufferedReader(new InputStreamReader(System.in))) long N = scan.nextLong(); N scan.nextLong() scan.nextLong scan c(N) c N public void c(long N) {
        StringBuilder sb = new StringBuilder();
        while(0 < N) {
            N -= 1;
            int mod = (int) (N % 26);
            sb.append((char)(mod + (int)'a'));
            N /= 26;
        }
        System.out.println(sb.reverse().toString());
    } c {
        StringBuilder sb = new StringBuilder();
        while(0 < N) {
            N -= 1;
            int mod = (int) (N % 26);
            sb.append((char)(mod + (int)'a'));
            N /= 26;
        }
        System.out.println(sb.reverse().toString());
    } StringBuilder sb = new StringBuilder(); sb new StringBuilder() while(0 < N) {
            N -= 1;
            int mod = (int) (N % 26);
            sb.append((char)(mod + (int)'a'));
            N /= 26;
        } 0 < N 0 N {
            N -= 1;
            int mod = (int) (N % 26);
            sb.append((char)(mod + (int)'a'));
            N /= 26;
        } N -= 1 N 1 int mod = (int) (N % 26); mod (int) (N % 26) N 26 sb.append((char)(mod + (int)'a')) sb.append sb (char)(mod + (int)'a') mod (int)'a' N /= 26 N 26 System.out.println(sb.reverse().toString()) System.out.println System.out System System.out sb.reverse().toString() sb.reverse().toString sb.reverse() sb.reverse sb long N N public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        long N = scan.nextLong();
        c(N);
    }
    public void c(long N) {
        StringBuilder sb = new StringBuilder();
        while(0 < N) {
            N -= 1;
            int mod = (int) (N % 26);
            sb.append((char)(mod + (int)'a'));
            N /= 26;
        }
        System.out.println(sb.reverse().toString());
    }
} public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        long N = scan.nextLong();
        c(N);
    }
    public void c(long N) {
        StringBuilder sb = new StringBuilder();
        while(0 < N) {
            N -= 1;
            int mod = (int) (N % 26);
            sb.append((char)(mod + (int)'a'));
            N /= 26;
        }
        System.out.println(sb.reverse().toString());
    }
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        long N = scan.nextLong();
        c(N);
    }
    public void c(long N) {
        StringBuilder sb = new StringBuilder();
        while(0 < N) {
            N -= 1;
            int mod = (int) (N % 26);
            sb.append((char)(mod + (int)'a'));
            N /= 26;
        }
        System.out.println(sb.reverse().toString());
    }
}
