UVa 10170

#include<bits/stdc++.h>
#define ll long long

using namespace std;

int main()
{
 ll s,d,n,i;

 while(cin>>s>>d)
 {
  n=0;
  for(i=s;;i++){

   n+=i;
   if(n>d || n==d) {
    cout<<i<<endl;
    break;
   }
  }
 }
 return 0;
}