WA on Subtask #6

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define mat __int128
int t,n,m,ans;
bool check(mat x){
	mat a=x/2,b=x-a;
	mat c=(a+b)*(a+b)-(a+b)*(n+m)+(mat)(n*m);
	if(a*b>=c) return 1;
	return 0;
}
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);cout.tie(0);
	cin>>t;
	while(t--){
		cin>>n>>m;
		ans=ceil((mat)(n+m-sqrtl((mat)n*n+(mat)m*m-(mat)n*m))*2ll/3ll);
		if(check(ans-1ll)) ans--;
		else if(!check(ans)) ans++;
		cout<<ans<<'\n';
	}
	return 0;
}