class Solution {
public:
    bool isHappy(int n) {

        while(true)
        {
            int sum = 0;
            while(n!=0)
            {
                int lastDigit = n % 10;
                sum += lastDigit*lastDigit;
                n = n/10;
            }

            if(1 <= sum && sum <= 9)
            {
                if(sum == 1 || sum == 7)
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
            else
            {
                n = sum;
            }
        }

    }
};