import java.io.FileNotFoundException;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	long N = sc.nextLong();
    	if(N==1) {
    		System.out.println("a");
    	} else {

    		long X = 26;
    		int cnt = 0;
    		while(X<N) {
    			X = 26 * (X+1);
    			cnt++;
    		}
    		X = X/26 -1 ;
        	N = N-X-1;
        	long[] x = new long[11];
        	int keta = 0;
        	while(N>0) {
        		x[keta] = N%26;
        		keta++;
        		N = N/26;
        	}
        	for(int i=cnt;i>=0;i--) {
        		if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		}
        	}
    	}
    }
} import java.io.FileNotFoundException; FileNotFoundException java.io import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	long N = sc.nextLong();
    	if(N==1) {
    		System.out.println("a");
    	} else {

    		long X = 26;
    		int cnt = 0;
    		while(X<N) {
    			X = 26 * (X+1);
    			cnt++;
    		}
    		X = X/26 -1 ;
        	N = N-X-1;
        	long[] x = new long[11];
        	int keta = 0;
        	while(N>0) {
        		x[keta] = N%26;
        		keta++;
        		N = N/26;
        	}
        	for(int i=cnt;i>=0;i--) {
        		if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		}
        	}
    	}
    }
} Main public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	long N = sc.nextLong();
    	if(N==1) {
    		System.out.println("a");
    	} else {

    		long X = 26;
    		int cnt = 0;
    		while(X<N) {
    			X = 26 * (X+1);
    			cnt++;
    		}
    		X = X/26 -1 ;
        	N = N-X-1;
        	long[] x = new long[11];
        	int keta = 0;
        	while(N>0) {
        		x[keta] = N%26;
        		keta++;
        		N = N/26;
        	}
        	for(int i=cnt;i>=0;i--) {
        		if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		}
        	}
    	}
    } main {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	long N = sc.nextLong();
    	if(N==1) {
    		System.out.println("a");
    	} else {

    		long X = 26;
    		int cnt = 0;
    		while(X<N) {
    			X = 26 * (X+1);
    			cnt++;
    		}
    		X = X/26 -1 ;
        	N = N-X-1;
        	long[] x = new long[11];
        	int keta = 0;
        	while(N>0) {
        		x[keta] = N%26;
        		keta++;
        		N = N/26;
        	}
        	for(int i=cnt;i>=0;i--) {
        		if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		}
        	}
    	}
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long N = sc.nextLong(); N sc.nextLong() sc.nextLong sc if(N==1) {
    		System.out.println("a");
    	} else {

    		long X = 26;
    		int cnt = 0;
    		while(X<N) {
    			X = 26 * (X+1);
    			cnt++;
    		}
    		X = X/26 -1 ;
        	N = N-X-1;
        	long[] x = new long[11];
        	int keta = 0;
        	while(N>0) {
        		x[keta] = N%26;
        		keta++;
        		N = N/26;
        	}
        	for(int i=cnt;i>=0;i--) {
        		if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		}
        	}
    	} N==1 N 1 {
    		System.out.println("a");
    	} System.out.println("a") System.out.println System.out System System.out "a" {

    		long X = 26;
    		int cnt = 0;
    		while(X<N) {
    			X = 26 * (X+1);
    			cnt++;
    		}
    		X = X/26 -1 ;
        	N = N-X-1;
        	long[] x = new long[11];
        	int keta = 0;
        	while(N>0) {
        		x[keta] = N%26;
        		keta++;
        		N = N/26;
        	}
        	for(int i=cnt;i>=0;i--) {
        		if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		}
        	}
    	} long X = 26; X 26 int cnt = 0; cnt 0 while(X<N) {
    			X = 26 * (X+1);
    			cnt++;
    		} X<N X N {
    			X = 26 * (X+1);
    			cnt++;
    		} X = 26 * (X+1) X 26 * (X+1) 26 (X+1) X 1 cnt++ cnt X = X/26 -1 X X/26 -1 X/26 X 26 1 N = N-X-1 N N-X-1 N-X-1 N X 1 long[] x = new long[11]; x new long[11] 11 int keta = 0; keta 0 while(N>0) {
        		x[keta] = N%26;
        		keta++;
        		N = N/26;
        	} N>0 N 0 {
        		x[keta] = N%26;
        		keta++;
        		N = N/26;
        	} x[keta] = N%26 x[keta] x keta N%26 N 26 keta++ keta N = N/26 N N/26 N 26 for(int i=cnt;i>=0;i--) {
        		if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		}
        	} int i=cnt; int i=cnt; i cnt i>=0 i 0 i-- i-- i {
        		if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		}
        	} {
        		if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		}
        	} if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		} i>0 i 0 {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} long y = x[i]; y x[i] x i long codepoint =  97+y; codepoint 97+y 97 y char c = (char)codepoint; c (char)codepoint System.out.print(c) System.out.print System.out System System.out c {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		} long y = x[i]; y x[i] x i y++ y long codepoint =  96+y; codepoint 96+y 96 y char c = (char)codepoint; c (char)codepoint System.out.println(c) System.out.println System.out System System.out c String[] args args public class Main {
    public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	long N = sc.nextLong();
    	if(N==1) {
    		System.out.println("a");
    	} else {

    		long X = 26;
    		int cnt = 0;
    		while(X<N) {
    			X = 26 * (X+1);
    			cnt++;
    		}
    		X = X/26 -1 ;
        	N = N-X-1;
        	long[] x = new long[11];
        	int keta = 0;
        	while(N>0) {
        		x[keta] = N%26;
        		keta++;
        		N = N/26;
        	}
        	for(int i=cnt;i>=0;i--) {
        		if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		}
        	}
    	}
    }
} public class Main {
    public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	long N = sc.nextLong();
    	if(N==1) {
    		System.out.println("a");
    	} else {

    		long X = 26;
    		int cnt = 0;
    		while(X<N) {
    			X = 26 * (X+1);
    			cnt++;
    		}
    		X = X/26 -1 ;
        	N = N-X-1;
        	long[] x = new long[11];
        	int keta = 0;
        	while(N>0) {
        		x[keta] = N%26;
        		keta++;
        		N = N/26;
        	}
        	for(int i=cnt;i>=0;i--) {
        		if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		}
        	}
    	}
    }
} Main
import java.io.FileNotFoundException;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	long N = sc.nextLong();
    	if(N==1) {
    		System.out.println("a");
    	} else {

    		long X = 26;
    		int cnt = 0;
    		while(X<N) {
    			X = 26 * (X+1);
    			cnt++;
    		}
    		X = X/26 -1 ;
        	N = N-X-1;
        	long[] x = new long[11];
        	int keta = 0;
        	while(N>0) {
        		x[keta] = N%26;
        		keta++;
        		N = N/26;
        	}
        	for(int i=cnt;i>=0;i--) {
        		if(i>0) {
        			long y = x[i];
        			long codepoint =  97+y;
        			char c = (char)codepoint;
        			System.out.print(c);
        		} else {
        			long y = x[i];
        			y++;
        			long codepoint =  96+y;
        			char c = (char)codepoint;
        			System.out.println(c);
        		}
        	}
    	}
    }
}