#include <bits/stdc++.h>
using namespace std;

ifstream in("energii.in");
ofstream out("energii.out");

int w,g,eg[1005],ec[1005];
void read(){
in>>g>>w;
for(int i=1;i<=g;i++)
in>>eg[i]>>ec[i];
}

void solve(){
int s=0,s1=0,mini=99999999;
for(int i=1;i<=g;i++)
for(int j=i;j<=g;j++)
{
 s=0;
 s1=0;
 s=s+eg[j];
 s1=s1+ec[j];
 if(s==w&&s1<mini)
  mini=s1;
}
out<<mini;
}


int main(){
read();
solve();

return 0;

}