1 #include <iostream>
2 #include <string.h>
3 #include <string>
4 #include <fstream>
5 #include <algorithm>
6 #include <stdio.h>
7 #include <vector>
8 #include <queue>
9 #include <set>
10 #include <cmath>
11 using namespace std;
12 const double eps = 1e-8;
13 const int INF=0x7fffffff;
14 unsigned long long uINF = ~0LL;
15 #define MAXN 10000007
16 typedef long long LL;
17 LL vis[MAXN];
18 LL prime[MAXN];
19
20 void sieve(LL n)
21 {
22 LL m=(LL)sqrt(n+0.5);
23 memset(vis,0,sizeof(vis));
24 for(LL i=2;i<=m;i++)if(!vis[i])
25 for(LL j=i*i;j<=n;j+=i)vis[j]=1;
26 }
27
28 LL gen_prime(LL n)
29 {
30 sieve(n);
31 LL c=0;
32 for(LL i=2;i<=n;i++)if(!vis[i])
33 prime[c++]=i;
34 return c;
35 }
36
37 LL gcd(LL a,LL b)
38 {
39 return b==0?a:gcd(b,a%b);
40 }
41 LL num[11];
42 LL ex[11];
43 void init()
44 {
45 num[0]=1;ex[0]=0;
46 num[1]=9;ex[1]=1;
47 for(int i=2;i<=10;i++)
48 {num[i]=num[i-1]*10;
49 ex[i]=ex[i-1]*10;}
50
51 //for(int i=1;i<11;i++)
52 //cout<<num[i]<<' ';
53 }
54
55 string Reverse(string str1)
56 {
57 string str2="";
58 for(int i=str1.length()-1;i>=0;i--)
59 str2+=str1[i];
60 return str2;
61 }
62
63 int main()
64 {
65 LL n;
66 init();
67 while(scanf("%lld",&n),n)
68 {
69 int i;
70 string ans="";
71 bool odds;
72 LL dig=1;
73 for(i=1;i<11;i++)
74 {
75 if(n>num[i])n-=num[i];
76 else {odds=true;break;}
77 if(n>num[i])n-=num[i];
78 else {odds=false;break;}
79 dig*=10;
80 }
81 n--;n+=dig;
82 while(n>0)
83 {
84 ans+=n%10+'0';
85 n/=10;
86 }
87 ans=Reverse(ans);
88 if(odds)ans+=Reverse(ans.substr(0,ans.length()-1));
89 else ans+=Reverse(ans);
90 cout<<ans<<endl;
91 }
92
93 return 0;
94 }
