/*
TASK:lift
LANG C++
*/
#include<iostream>
#include<stdio.h>
using namespace std;
struct qw{int h,g;} Q[20];
double M[20];
int N,T;
void vhod()
{cin>>N>>T;
 for(int i=1;i<=N;i++)
  cin>>Q[i].h>>Q[i].g;
   
} 
void solve()
{int br=0,min=0;
 for(int i=1;i<=N;i++)
  {br+=Q[i].g;if(Q[i].h>min)min=Q[i].h;}
 if(br<=T){cout<<min<<"\n";return;}
  cout<<"0\n";
 
}
int main()
{vhod();
 solve();
}      
