99681
 8
 831
 9
 233
 1926
 7
 39393
 4
 2
 5
 1
 14514
 99998
 418
 82944
 11
 100000
 1317
 6
 10
 0
 25252

aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 aaaabbcc
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbcc
 aaaabbb
 aaaaaaaaaaaaaaaaaaaaaabbcc
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbccccdd
 aaaabb
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbccccddee
 aaabb
 aabb
 aaabbcc
 aa
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbcccccddd
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccddee
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbccdd
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbcccccccddee
 aaaaabb
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccdddee
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbcccc
 aaaa
 aaaaa
 a
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbccccdd

import java.io.*;
import java.util.*;

public class main {
	private static InputStream stream;
	private static byte[] buf = new byte[1024];
	private static int curChar;
	private static int numChars;
	private static SpaceCharFilter filter;
	private static PrintWriter pw;
	private static long mod = 1000000000 + 7;
	private static long mod1 = 1000000000 + 9;
	private static int MAX=1000001;
	private static int block;
	//private static int[] dfs1;
	private static int[] tin;
	private static int[] tout;
	//private static Node[] nodes1;
	//private static ArrayList<Integer>[] list;
	private static void soln(){
		int k=nextInt();
		int[] cnt=new int[26];
		for(int i=0;i<26;i++) {
			int sum=0;
			int c=0;
			for(int j=1;j<=k;j++) {
				if((sum+j)<=k) {
					sum+=j;
				}else
					break;
				c++;
			}
			k-=sum;
			cnt[i]=c;
		}
		StringBuilder sb=new StringBuilder();
		for(int i=0;i<26;i++) {
			for(int j=0;j<=cnt[i];j++)
				sb.append((char)('a'+i));
		}
		pw.println(sb.toString());
	}
	private static void dfs(int cur,int prev,LinkedList<Integer>[] tree,int[][] ans,int[] arr) {
		Iterator<Integer> it=tree[cur].listIterator();
		while(it.hasNext()) {
			int x=it.next();
			if(x!=prev) {
				if(cur==0) {
					ans[x][0]=(int) gcd(ans[cur][0],arr[x]);
					ans[x][1]=Math.max(arr[x],arr[0]);
				}else{
					ans[x][0]=(int) gcd(ans[cur][0],arr[x]);
					ans[x][1]=(int) Math.max(gcd(ans[cur][1],arr[x]),ans[cur][0]);
					ans[x][1]=(int)Math.max(ans[x][1],gcd(ans[prev][0],arr[x]));
					ans[x][1]=(int)Math.max(ans[x][1],gcd(gcd(ans[prev][1],arr[x]),arr[cur]));
				}
			//	System.out.println(ans[x][0]+" "+ans[x][1]);
				dfs(x,cur,tree,ans,arr);
			}
		}
	}
	public static class Segment {
		private int[] tree;
		private int size;
		private int n;
		private class node{
			private int a;
			private int b;
			private int c;
			public node(int x,int y,int z){
				a=x;
				b=y;
				c=z;
			}
		}
		public Segment(int n){
			//this.base=arr;
			int x = (int) (Math.ceil(Math.log(n) / Math.log(2)));
	        size = 2 * (int) Math.pow(2, x) - 1;
			tree=new int[size];
			this.n=n;
			//build(0,0,n-1);
		}
		public int query(int l,int r){
			return queryUtil(l,r,0,0,n-1);
		}
		private int queryUtil(int x,int y,int id,int l,int r){
			if(l>y || x>r) 
				return 0;
			if(x <= l && r<=y)
				return tree[id];
			int mid=l+(r-l)/2;
			return queryUtil(x,y,2*id+1,l,mid)+queryUtil(x,y,2*id+2,mid+1,r);
		}
		public void update(int x,int colour,int id,int l,int r){
			//System.out.println(l+" "+r+" "+x);
			if(x>r || x<l)
				return;
			if(l==r){
				tree[id]+=colour;
				return;
			}
			int mid=l+(r-l)/2;
			update(x,colour,2*id+1,l,mid);
			update(x,colour,2*id+2,mid+1,r);
			tree[id]=tree[2*id+1]+tree[2*id+2];
		}
	}
	private static class Pair implements Comparable<Pair>{
		int v,i;
		public Pair(int a,int b){
			v=a;
			i=b;
		}
		@Override
		public int compareTo(Pair arg0) {
			return this.v-arg0.v;
		}
	}
	public static class Merge {
	public void sort(int inputArr[]) {
        int length = inputArr.length;
        doMergeSort(inputArr,0, length - 1);
    }
    private void doMergeSort(int[] arr,int lowerIndex, int higherIndex) {         
        if (lowerIndex < higherIndex) {
            int middle = lowerIndex + (higherIndex - lowerIndex) / 2;
            doMergeSort(arr,lowerIndex, middle);
            doMergeSort(arr,middle + 1, higherIndex);
            mergeParts(arr,lowerIndex, middle, higherIndex);
        }
    }
    private void mergeParts(int[]array,int lowerIndex, int middle, int higherIndex) {
    	int[] temp=new int[higherIndex-lowerIndex+1];
        for (int i = lowerIndex; i <= higherIndex; i++) {
            temp[i-lowerIndex] = array[i];
        }
        int i = lowerIndex;
        int j = middle + 1;
        int k = lowerIndex;
        while (i <= middle && j <= higherIndex) {
            if (temp[i-lowerIndex] < temp[j-lowerIndex]) {
                array[k] = temp[i-lowerIndex];
                i++;
            } else {
                array[k] = temp[j-lowerIndex];
                j++;
                //cnt+=(middle+1-i);
            }
            k++;
        }
        while (i <= middle) {
            array[k] = temp[i-lowerIndex];
            k++;
            i++;
        }
        while(j<=higherIndex){
        	array[k]=temp[j-lowerIndex];
        	k++;
        	j++;
        }
        /*pw.println(lowerIndex+" "+higherIndex);
        for(int m=lowerIndex;m<=higherIndex;m++)
        	pw.print(array[m]+" ");
        pw.println();*/
    }
}
	private static class DSU{
		int[] parent;
		int[] rank;
		int cnt;
		public DSU(int n){
			parent=new int[n];
			rank=new int[n];
			for(int i=0;i<n;i++){
				parent[i]=i;
				rank[i]=1;
			}
			cnt=n;
		}
		int find(int i){
	        while(parent[i] !=i){
	        	parent[i]=parent[parent[i]];
	        	i=parent[i];
	        }
	        return i;
	    }
		int Union(int x, int y){
	        int xset = find(x);
	        int yset = find(y);
	        if(xset!=yset)
	        	cnt--;
	        if(rank[xset]<rank[yset]){
	        	parent[xset] = yset;
		        rank[yset]+=rank[xset];
		        rank[xset]=0;
		        return yset;
	        }else{
	        	parent[yset]=xset;
	        	rank[xset]+=rank[yset];
	        	rank[yset]=0;
	        	return xset;
	        }
	    }
	}
	static void multiply(long[][] a, long[][] b,long m){
		int n=a.length;
	    long[][] mul=new long[n][n];
	    for (int i = 0; i < n; i++){
	        for (int j = 0; j < n; j++){
	            mul[i][j] = 0;
	            for (int k = 0; k < n; k++)
	                mul[i][j] = (mul[i][j]+(a[i][k]*b[k][j])%m)%m;
	        }
	    }
	    for (int i=0; i<n; i++)
	        for (int j=0; j<n; j++)
	            a[i][j] =mul[i][j];
	}
	private static long pow(long a, long b, long c) {
		if (b == 0)
			return 1;
		long p = pow(a, b / 2, c);
		p = (p * p) % c;
		return (b % 2 == 0) ? p : (a * p) % c;
	}
	
	private static class Mo implements Comparable<Mo>{
		int l;
		int r;
		int i;
		public Mo(int a,int b,int ind) {
			l=a;r=b;i=ind;
		}
		@Override
		public int compareTo(Mo arg0) {
			int b1=this.l/block;
			int b2=arg0.l/block;
			return (b1!=b2)?(b1-b2):(this.r-arg0.r);
		}
	}

	private static long gcd(long n, long l) {
		if (l == 0)
			return n;
		return gcd(l, n % l);
	}

	private static long max(long a, long b) {
		if (a > b)
			return a;
		return b;
	}

	private static long min(long a, long b) {
		if (a < b)
			return a;
		return b;
	}

	public static void main(String[] args) throws Exception {
		new Thread(null,new Runnable(){
			@Override
			public void run() {
				/*try {
					InputReader(new FileInputStream("C:\\Users\\hardik\\Desktop\\C-small-1-attempt1.in"));
				} catch (FileNotFoundException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}*/
				InputReader(System.in);
				pw = new PrintWriter(System.out);
				/*try {
					pw=new PrintWriter(new FileOutputStream("C:\\Users\\hardik\\Desktop\\out.txt"));
				} catch (FileNotFoundException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}*/
				soln();
				pw.close();
			}
		},"1",1<<26).start();
	}

	public static void InputReader(InputStream stream1) {
		stream = stream1;
	}

	private static boolean isWhitespace(int c) {
		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	}

	private static boolean isEndOfLine(int c) {
		return c == '\n' || c == '\r' || c == -1;
	}

	private static int read() {
		if (numChars == -1)
			throw new InputMismatchException();
		if (curChar >= numChars) {
			curChar = 0;
			try {
				numChars = stream.read(buf);
			} catch (IOException e) {
				throw new InputMismatchException();
			}
			if (numChars <= 0)
				return -1;
		}
		return buf[curChar++];
	}

	private static int nextInt() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-') {
			sgn = -1;
			c = read();
		}
		int res = 0;
		do {
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(c));
		return res * sgn;
	}

	private static long nextLong() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-') {
			sgn = -1;
			c = read();
		}
		long res = 0;
		do {
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(c));
		return res * sgn;
	}

	private static String nextToken() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do {
			res.appendCodePoint(c);
			c = read();
		} while (!isSpaceChar(c));
		return res.toString();
	}

	private static String nextLine() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do {
			res.appendCodePoint(c);
			c = read();
		} while (!isEndOfLine(c));
		return res.toString();
	}

	private static int[] nextIntArray(int n) {
		int[] arr = new int[n];
		for (int i = 0; i < n; i++) {
			arr[i] = nextInt();
		}
		return arr;
	}

	private static long[] nextLongArray(int n) {
		long[] arr = new long[n];
		for (int i = 0; i < n; i++) {
			arr[i] = nextLong();
		}
		return arr;
	}

	private static void pArray(int[] arr) {
		for (int i = 0; i < arr.length; i++) {
			System.out.print(arr[i] + " ");
		}
		System.out.println();
		return;
	}

	private static void pArray(long[] arr) {
		for (int i = 0; i < arr.length; i++) {
			System.out.print(arr[i] + " ");
		}
		System.out.println();
		return;
	}

	private static boolean isSpaceChar(int c) {
		if (filter != null)
			return filter.isSpaceChar(c);
		return isWhitespace(c);
	}
	private static char nextChar() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		char c1=(char)c;
		while(!isSpaceChar(c))
			c=read();
		return c1;
	}
	private interface SpaceCharFilter {
		public boolean isSpaceChar(int ch);
	}
}