You are given a positive integer num consisting only of digits 6 and 9.

Return the maximum number you can get by changing at most one digit (6 becomes 9, and 9 becomes 6).

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Example 1:

Input: num = 9669
Output: 9969
Explanation: 
Changing the first digit results in 6669.
Changing the second digit results in 9969.
Changing the third digit results in 9699.
Changing the fourth digit results in 9666.
The maximum number is 9969.


Example 2:

Input: num = 9996
Output: 9999
Explanation: Changing the last digit 6 to 9 results in the maximum number.


Example 3:

Input: num = 9999
Output: 9999
Explanation: It is better not to apply any change.


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Constraints:


	1 &lt;= num &lt;= 104
	num&nbsp;consists of only 6 and 9 digits.


class Solution:
    def maximum69Number(self, num):
        lst= list(str(num)) #! convert the number to a list
        for i in range(len(lst)): #! iterate through the list
            if lst[i]=='6': #! if the element is 6
                lst[i]='9' #! replace the element with 9
                break #! break the loop
        return int(''.join(lst))  #! convert the list to a number
class Solution {
    public int maximum69Number (int num) {
        int i;
        String s=String.valueOf(num);
        int l=s.length();
        int max=num;
        
        for(i=0;i<l;i++)
        {
            char c[]=s.toCharArray();
            if(c[i]=='9')
            {
                c[i]='6';
            }
            else
            {
                c[i]='9';
            }
            String p=new String(c);
            int k=Integer.parseInt(p);
            max=Math.max(max,k);
        }
        return max;
    }
}
class Solution {
public:
    int maximum69Number (int num) {
        string s=to_string(num);
        for(int i=0;i<s.size();i++){
            if(s[i]=='6'){
                 s[i]='9';
                break;
            }
               
        }
        num=stoi(s);
        return num;
    }
};
var maximum69Number = function(num) {
  let flag=true
   num= num.toString().split('').map((x)=>{
        if(x!=='9'&&flag){
            flag=false
            return '9'
        }
        return x
    })
    return parseInt(num.join(''))
};
Maximum 69 Number