#include <iostream>
#include<bits/stdc++.h>
using namespace std;
 
int findsum(vector<int>& dp,int x,int y,int len)
{
 
	dp[0]=x;
	  int i=1;
	  while(x<=y)
	  {
		  x++;
		  dp[i]=dp[i-1]+x;
		  i++;
	  }
	  return dp[len];
}
int main()
{
  int tc;
  cin >> tc;
  while(tc--)
  {
 
  int x ,y;
  cin >> x>> y;
	int len = y-x;
	vector<int> dp(len+1);
  int ans=findsum(dp,x,y,len);	  
  cout << ans << endl;
	  dp.clear();
  }	  
	return 0;
}

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MgoxIDUKMyAxMA==

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