1001 A+B Format (20分)

#include<iostream>
#include<algorithm>
#include<cstring>
#include<string>
#include<cstdio>
#include<cctype>
#include<cmath>
#include<vector>
#include<queue>
#include<set>
#include<map>
#include<stack>
#include<sstream>
#define mm(a,x) memset(a,x,sizeof(a))
#define maxn 100005
using namespace std;
typedef long long ll;
const int INF=0x3f3f3f3f;

int main()
{
   
   std::ios::sync_with_stdio(false);
   std::cin.tie(0);
	int a,b;
	cin>>a>>b;
	string s=to_string(a+b);
	for(int i=0;i<s.length();i++)
	{
   
		cout<<s[i];
		if(s[i]=='-') continue;
		if((i+1)%3==s.length()%3&&i!=s.length()-1)
		cout<<",";
	}
}