void main(){
  import std.stdio, std.string, std.conv, std.algorithm;
  import std.typecons;

  int n; long wmax; rd(n, wmax);
  alias T=Tuple!(long, "v", long, "w");
  auto a=new T[](n);
  foreach(i; 0..n) rd(a[i].v, a[i].w);

  sort!((x, y)=>((1.*x.v/x.w)>(1.*y.v/y.w)))(a);
  long vsum=0, wsum=0;
  foreach(e; a){
    if((wsum+e.w)<=wmax){
      vsum+=e.v;
      wsum+=e.w;
    }
  }

  writeln(vsum);
}

void rd(T...)(ref T x){
  import std.stdio, std.string, std.conv;
  auto l=readln.split;
  assert(l.length==x.length);
  foreach(i, ref e; x){
    e=l[i].to!(typeof(e));
  }
}
void wr(T...)(T x){
  import std.stdio;
  foreach(e; x) stderr.write(e, " ");
  stderr.writeln();
}