int f(int n){
    int b = n, a = n,sum = 0;
    int cnt = 0;
    while(b != 0){
        b = b / 10;
        cnt++;
    }
    int i = cnt - 1;
    while(a != 0){
        sum = sum + (a % 10) * bpow(10, i);
        a = a / 10;
        i--;
    }
    if(sum + n == k)
        return true;
    return false;
}