unordered_map<char,int> mp;
    
    for(int i=0;i<s.size();i++)
    {
        mp[s[i]]++;
    }
    
int ans;
    
    for(int i=0;i<s.size();i++)
    {
        if(mp[s[i]]==1)                //elements repeaated one times 
        {
            ans=i;
        
             break;                //after searching first element break the loop.  
        }
        
        else
        {
            ans=-1;
        }
    }
    
    return ans;
    
    
    
}