import core.bitop;
import std.algorithm;
import std.ascii;
import std.bigint;
import std.conv;
import std.functional;
import std.format;
import std.math;
import std.numeric;
import std.range;
import std.stdio;
import std.string;
import std.random;
import std.typecons;

alias sread = () => readln.chomp();
alias Point2 = Tuple!(long, "y", long, "x");

T lread(T = long)()
{
    return readln.chomp.to!T();
}

T[] aryread(T = long)()
{
    return readln.split.to!(T[])();
}

void scan(TList...)(ref TList Args)
{
    auto line = readln.split();
    foreach (i, T; TList)
    {
        T val = line[i].to!(T);
        Args[i] = val;
    }
}

enum MOD = (10 ^^ 9) + 7;

void main()
{
    long N, K;
    scan(N, K);
    long[10 ^^ 5 + 1] B;
    foreach (_; 0 .. N)
    {
        long a, b;
        scan(a, b);
        B[a] += b;
    }
    long sum;
    foreach (i; 0 .. 10 ^^ 5 + 1)
    {
        sum += B[i];
        if (K <= sum)
        {
            writeln(i);
            return;
        }
    }
}
