Codeforces 514A- Chewbaсca and Number

Clicke here to view the problem
/***
Md. Namzul Hasan
Shahjalal University of Science & Technology,Sylhet.
hasan08sust@gmail.com
***/
#include<bits/stdc++.h>
using namespace std ;
typedef long long ll ;
typedef int in ;
typedef unsigned long long ull ;
const double pi = 2*acos(0) ;
#define maxi 40000
#define pf printf
#define sc scanf
#define pb push_back
#define MEM(x,y) (memset((x),(y),sizeof(x)))
#define MIN(x,y) ((x) < (y) ? (x) : (y))
#define MAX(x,y) ((x) > (y) ? (x) : (y))
#define load(array,size)  for(int i=0 ; i<size ; i++) cin>>array[i]  ;
#define new_line  pf("\n")
#define clear_data(array) memset(array,0,sizeof(array))
#define highest_int 2147483647

int main()
{
    string str ;
    int i,k,t ;

    cin>>str ;
    for(i=0 ;i<str.size() ;i++)
    {
        t = str[i] - '0' ;
        k = 9 -t ;
        if(k<t)
        {
            if(i==0 && k==0)
                continue ;
            str[i] = k + '0' ;
        }
    }
    cout<<str ;
    return 0;
}