而不是打折

@金泓镒 标题应该是打折优惠

using namespace std;
int main(){
    int n;
    cin>>n;
    int s=0;
    while(n!=0){
    	s+=n%10;
    	n/=10;
	}
	while(s>=10){
		int x=s,h=0;
		while(x!=0){
			h+=x%10;
			x/=10;
		}
		s=h;
	}
	cout<<s;
    return 0;
}