import java.util.*; 
import java.io.*;
import java.sql.Array;
import java.util.stream.*;
import java.util.function.*;

class Main implements Runnable
{ 

    void solve()
    {       
        int N = in.nextInt() , W = in.nextInt();
        ArrayList<ip> l = new ArrayList<>();
        int ans = -1 ;
        for(int i = 0 ; i < N ; i ++ )
        {
            int v = in.nextInt() , w = in.nextInt();
            if(w <= W) ans = Math.max(ans , v);
        }
        out.print(ans);
    }  
    
    public static void main(String[] args) 
    {
        new Thread(null, new Main(), "", Runtime.getRuntime().maxMemory()).start(); 
    }

    public void run() 
    {   
        solve();
        out.flush();
    }
    record ip(int fi , int se) { public String toString() { return fi +" "+ se ;} }
    record lp(long fi , long se) { public String toString() { return fi +" "+ se ;} }
    public double dist(lp p1 , lp p2) { return Math.sqrt((p1.fi - p2.fi) * (p1.fi - p2.fi) + (p1.se - p2.se) * (p1.se - p2.se)); }
    public int max(int ... a) { int max = -1 ; for(int p : a) max = Math.max(max , p); return max; }
    public int min(int ... a) { int min = Integer.MAX_VALUE ; for(int p : a) min = Math.min(min , p); return min; }
    public long max(long ... a) { long max = -1 ; for(long p : a) max = Math.max(max , p); return max; }
    public long min(long ... a) { long min = Long.MAX_VALUE ; for(long p : a) min = Math.min(min , p); return min; }
    public int sum(int ... a) { int sum = 0 ; for(int p : a) sum += p ; return sum ;}
    public long sum(long ... a) { long sum = 0 ; for(long p : a) sum += p ; return sum ;}
    public int abs(int a , int b) { return (int) Math.abs(a - b) ; }
    public long abs(long a , long b) { return (long) Math.abs(a - b) ; }
    public int pow(int a , int b) { return (int) Math.pow(a , b) ; }
    public long pow(long a , long b) { return (long) Math.pow(a , b) ; }
    public long rec(long a) { return a == 1 ? 1 : a * rec(a - 1); }
    public long [] recmod(int a , long MOD) { long [] recMod = new long[1 << 17] ; recMod[1] = 1 ; for(int i = 2 ; i < (1 << 17) ; i ++ ) recMod[i] = (recMod[i - 1] * i) % MOD9; return recMod; }
    public int [] rev(int [] a) { int [] r = new int[a.length] ; int idx = a.length ; for(int p : a) r[--idx] = p ; return r ; }
    public long [] rev(long [] a) { long [] r = new long[a.length] ; int idx = a.length ; for(long p : a) r[--idx] = p ; return r ; }
    public int gcd(int a, int b) { return b == 0 ? a: gcd(b, a % b); }
    public int lcm(int a, int b) { return a / gcd(a, b) * b; }
    public long gcd(long a, long b) { return b == 0 ? a: gcd(b, a % b); }
    public long lcm(long a, long b) { return a / gcd(a, b) * b; }
    public int gcd(int ... a) { int gcd = 0 ; for(int p : a) gcd = gcd(gcd , p) ; return gcd ; }
    public long gcd(long ... a) { long gcd = 0L ; for(long p : a) gcd = gcd(gcd , p) ; return gcd ; }
    public int lcm(int ... a) { int lcm = 1 ; for(int p : a) lcm = lcm(lcm , p) ; return lcm ; }
    public long lcm(long ... a) { long lcm = 1 ; for(long p : a) lcm = lcm(lcm , p) ; return lcm ; }
    public char upper(char c) { return (char)('A' + (c - 'a')); }
    public char lower(char c) { return (char)('a' + (c - 'A')); }
    public String yn(boolean a) { return a ? yes : no ; }
    public String rev(String a) { return new StringBuilder(a).reverse().toString(); }
    public void fill(int [] a , int v) { Arrays.fill(a , v); }
    public void fill(long [] a , long v) { Arrays.fill(a , v); }
    public void fill(int [][] a , int v) { for(int [] aa : a) fill(aa , v) ; }
    public void fill(long [][] a , long v) { for(long [] aa : a) fill(aa , v) ; }
    public void fill(int [][][] a , int v) { for(int [][] aa : a) fill(aa , v); }
    public void fill(long [][][] a , long v) { for(long [][] aa : a) fill(aa , v); }
    public int [] copy(int [] a) { return Arrays.copyOf(a , a.length); } 
    public long [] copy(long [] a) { return Arrays.copyOf(a , a.length); } 
    public String bin(int a , int len) { String b = Integer.toBinaryString(a); while(b.length() < len) b = "0" + b ; return b ; }
    public void debug(int [] a) { out.println(Arrays.toString(a)); fl();}
    public void debug(long [] a) { out.println(Arrays.toString(a)); fl();}
    public void debug(double [] a) { out.println(Arrays.toString(a)); fl();}
    public void debug(String [] a) { out.println(Arrays.toString(a)); fl();}
    public void debug(char [] a) { out.println(Arrays.toString(a)); fl();}
    public void debug(boolean [] a) { char [] c = conv(a); debug(c); fl();}
    public void debug(int [][] a) { for(int i = 0 ; i < a.length ; i ++ ) out.println(Arrays.toString(a[i])); fl();}
    public void debug(long [][] a) { for(int i = 0 ; i < a.length ; i ++ ) out.println(Arrays.toString(a[i])); fl();}
    public void debug(double [][] a) { for(int i = 0 ; i < a.length ; i ++ ) out.println(Arrays.toString(a[i])); fl();}
    public void debug(String [][] a) { for(int i = 0 ; i < a.length ; i ++ ) out.println(Arrays.toString(a[i])); fl();}
    public void debug(char [][] a) { for(int i = 0 ; i < a.length ; i ++ ) out.println(Arrays.toString(a[i])); fl();}
    public void debug(boolean [][] a) { char [][] c = new char [a.length][a[0].length] ; for(int i = 0 ; i < a.length ; i ++ ) c[i] = conv(a[i]) ; debug(c); fl();}
    private char [] conv(boolean [] a) { char [] c = new char[a.length] ; for(int i = 0 ; i < a.length ; i ++ ) c[i] = a[i] ? 'O' : 'X' ; return c ; }
    private void fl() { out.flush(); }

    PrintWriter out = new PrintWriter(System.out);
    In in = new In();
    static final long MOD7 = 1000000007;
    static final long MOD9 = 998244353;
    static final int  inf = (1  << 30);
    static final long lnf = (1L << 60);
    final String yes = "Yes";
    final String no  = "No" ;
    final char [] dir = {'U','R','D','L'};
    final int [] dy4 = {-1,0,1,0};
    final int [] dx4 = {0,1,0,-1};
    final int [] dy8 = {-1,-1,-1,0,1,1,1,0};
    final int [] dx8 = {-1,0,1,1,1,0,-1,-1};

}

class LazySegmentTree {
    final long[] Dat;
    final long[] Laz;
    final int N;
    final long E0;
    final long E1;
    final LongBinaryOperator F;
    final LongBinaryOperator G;
    final LongBinaryOperator H;
    final LongBinaryOperator P;
    final int[] Stack = new int[64];
    //初期配列 , dat(関与しない値) , lazy(関与しない値) , dat() , dat&lazy() , lazy() , lazy*len()
    public LazySegmentTree(int n, long e0, long e1, LongBinaryOperator f, LongBinaryOperator g, LongBinaryOperator h, LongBinaryOperator p) {
        this.E0 = e0;
        this.E1 = e1;
        this.F = f; this.G = g; this.H = h; this.P = p;
        int k = 1;
        while (k <= n) k <<= 1;
        this.Dat = new long[k << 1];
        this.Laz = new long[k << 1];
        this.N = k;
        Arrays.fill(Dat, E0);
        Arrays.fill(Laz, E1);
    }
    public LazySegmentTree(long[] src, long e0, long e1, LongBinaryOperator f, LongBinaryOperator g, LongBinaryOperator h, LongBinaryOperator p) {
        this(src.length, e0, e1, f, g, h, p);
        build(src);
    }
    private void build(long[] src) {
        System.arraycopy(src, 0, Dat, N, src.length);
        for (int i = N - 1; i > 0; i--) Dat[i] = F.applyAsLong(Dat[i << 1 | 0], Dat[i << 1 | 1]);
    }
    public void update(int l, int r, long v) {
        if (l >= r) return;
        int m = updown(l, r);
        l += N; r += N;
        for (; l < r; l >>= 1, r >>= 1) {
            if ((l & 1) != 0) {Laz[l] = H.applyAsLong(Laz[l], v); l++;}
            if ((r & 1) != 0) {r--; Laz[r] = H.applyAsLong(Laz[r], v);}
        }
        for (int i = 0; i < m; i++) {
            int k = Stack[i];
            Dat[k] = F.applyAsLong(calcDat(k << 1 | 0), calcDat(k << 1 | 1));
        }
    }
    public long query(int i) {
        int k = 1;
        int l = 0, r = N;
        while (k < N) {
            int kl = k << 1 | 0;
            int kr = k << 1 | 1;
            Dat[k] = F.applyAsLong(calcDat(kl), calcDat(kr));
            int m = (l + r) >> 1;
            if (m > i) {r = m; k = kl;} 
            else {l = m; k = kr;}
        }
        return Dat[k];
    }
    public long query(int l, int r) {
        if (l >= r) return E0;
        updown(l, r);
        long resL = E0, resR = E0;
        for (l += N, r += N; l < r; l >>= 1, r >>= 1) {
            if ((l & 1) != 0) resL = F.applyAsLong(resL, calcDat(l++));
            if ((r & 1) != 0) resR = F.applyAsLong(calcDat(--r), resR);
        }
        return F.applyAsLong(resL, resR);
    }
    private int updown(int l, int r) {
        if (l >= r) return 0;
        int i = 0;
        int kl = l + N, kr = r + N;
        for (int x = kl / (kl & -kl) >> 1, y = kr / (kr & -kr) >> 1; 0 < kl && kl < kr; kl >>= 1, kr >>= 1) {
            if (kl <= x) Stack[i++] = kl;
            if (kr <= y) Stack[i++] = kr;
        }
        for (; kl > 0; kl >>= 1) Stack[i++] = kl;
        int m = i;
        while (i > 0) calcDat(Stack[--i]);
        return m;
    }
    private long calcDat(int k) {
        long lz = Laz[k];
        if (lz != E1) {
            int w = N / Integer.highestOneBit(k);
            Dat[k] = G.applyAsLong(Dat[k], P.applyAsLong(lz, w));
            if (k < N) {
                int l = k << 1 | 0, r = k << 1 | 1;
                Laz[l] = H.applyAsLong(Laz[l], lz);
                Laz[r] = H.applyAsLong(Laz[r], lz);
            }
            Laz[k] = E1;
        }
        return Dat[k];
    }
    void debug()
    {
        for(int i = Dat.length - N ; i < Dat.length - 1; i ++ ) 
        {
            System.out.print(Dat[i]+" ");
        }
        System.out.println();
    }
}

final class WaveletMatrix {

    private final int[][] data;
    private final int n, bit;

    WaveletMatrix(int[] d, int bit) {
        n = d.length;
        this.bit = bit;
        int[] dat = d.clone();
        data = new int[bit][n];
        int[] que = new int[n];
        for (int k = bit - 1; k >= 0; k--) {
            int que1 = 0, que2 = n;
            for (int i = 0; i < n; i++) {
                if ((data[k][i] = (dat[i] >> k) & 1) == 1)
                    que[--que2] = dat[i];
                else
                    que[que1++] = dat[i];
            }
            for (int i = 0; i < que1; i++)
                dat[i] = que[i];
            for (int i = n - 1, j = que1; i >= que1; i--, j++)
                dat[j] = que[i];
            for (int i = 1; i < n; i++)
                data[k][i] += data[k][i - 1];
        }
    }

    WaveletMatrix(int[] dat) {
        this(dat, 31);
    }

    private final int get(int bi, int id) {
        if (id == 0)
            return data[bi][0];
        return data[bi][id] - data[bi][id - 1];
    }

    final int access(int idx) {
        int ans = 0;
        for (int k = bit - 1; k >= 0; k--) {
            if (get(k, idx) == 1) {
                ans |= 1 << k;
                idx = zer(k, n) + one(k, idx);
            } else
                idx -= data[k][idx];
        }
        return ans;
    }

    private final int one(int bi, int l) {
        if (l == 0)
            return 0;
        return data[bi][l - 1];
    }

    private final int zer(int bi, int l) {
        return l - one(bi, l);
    }

    private final int sum(int bi, int l, int r) {
        return one(bi, r) - one(bi, l);
    }

    public final int kth_smallest(int l, int r, int kth) {
        int ans = 0;
        for (int k = bit - 1; k >= 0; k--) {
            final int s = r - l - sum(k, l, r);
            if (kth < s) {
                l = zer(k, l);
                r = l + s;
            } else {
                kth -= s;
                ans |= 1 << k;
                final int ran = r - l - s;
                l = zer(k, n) + one(k, l);
                r = l + ran;
            }
        }
        return ans;
    }

    public final int kth_largest(int l, int r, int kth) {
        return kth_smallest(l, r, r - l - kth);
    }

    public final int count_lower(int l, int r, int lower) {
        int ans = 0;
        for (int k = bit - 1; k >= 0; k--) {
            final int s = r - l - sum(k, l, r);
            if (((lower >> k) & 1) == 1) {
                ans += s;
                final int ran = r - l - s;
                l = zer(k, n) + one(k, l);
                r = l + ran;
            } else {
                l = zer(k, l);
                r = l + s;
            }
        }
        return ans;
    }

    public final int count_upper(int l, int r, int upper) {
        return r - l - count_lower(l, r, upper + 1);
    }

    public final int count(int l, int r, int x) {
        return count_lower(l, r, x + 1) - count_lower(l, r, x);
    }

    public final int next_value(int l, int r, int upper) {
        final int cnt = count_lower(l, r, upper + 1);
        return kth_smallest(l, r, cnt);
    }

    public final int perv_value(int l, int r, int lower) {
        final int cnt = count_upper(l, r, lower - 1);
        return kth_largest(l, r, cnt);
    }
}

class UnionFind
{
    private int [] rank , parents , size , data , edges;
    private int groups ;
    private BinaryOperator<Integer> op ;
    private static BinaryOperator<Integer> def_op = (a, b) -> a;
    UnionFind(int N) { this(N , def_op) ; }
    UnionFind(int N , BinaryOperator<Integer> op)
    {
        this.rank = new int[N];
        this.parents = new int[N];
        this.size = new int[N];
        this.data = new int[N];
        this.edges = new int[N];
        this.groups = N ; 
        for(int i = 0 ; i < N ; i ++ )
        {
            parents[i] = i ;
            rank[i] = 0 ;
            size[i] = 1 ;
            data[i] = i ;
        }
        this.op = op ;
    }
    int Group() { return this.groups ; }
    int Edge(int x) { return edges[root(x)] ; }
    int Op(int x) { return data[root(x)] ; }
    int Size(int x) { return size[root(x)] ; }
    int root(int x) 
    {
        if(x == parents[x]) return x ;
        else parents[x] = root(parents[x]);
        return parents[x];
    }
    boolean same(int x , int y) { return root(x) == root(y) ; }
    void unite(int l , int r)
    {
        int left  = root(l);
        int right = root(r);
        int parent = -1 , child = -1 ;
        if(left == right) { ++ edges[right]; return ; }
        parent = rank[left] > rank[right] ? left : right;
        child = rank[left] > rank[right] ? right : left ;
        --groups;
        parents[child] = parent ;
        rank[child] ++ ;
        size[parent] += size[child] ; 
        edges[parent] += edges[child] + 1 ; 
        data[parent] = op.apply(data[child] , data[parent]);
    }
    List<List<Integer>> Groups() {
        List<List<Integer>> Group = new ArrayList<>();
        Map<Integer,List<Integer>> mp = new HashMap<>();
        for(int i = 0 ; i < parents.length ; i ++ ) 
        {
            int par = root(i);
            if(!mp.containsKey(par)) mp.put(par , new ArrayList<>());
            mp.get(par).add(i);
        }
        for(List<Integer> lists : mp.values()) Group.add(new ArrayList<>(lists));
        return Group;
    }
}

class In
{

    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;

    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }

    private int readByte() { 
        if (hasNextByte()) return buffer[ptr++]; else return -1;
    }

    private static boolean isPrintableChar(int c) { 
        return 33 <= c && c <= 126;
    }

    private  boolean hasNext() { 
        while(hasNextByte() && !isPrintableChar(buffer[ptr])) {
            ptr++; 
        }
        return hasNextByte();
    }

    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }

    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }

    public double nextDouble() { 
        return Double.parseDouble(next());
    }

    public char nextChar() {
        return next().charAt(0);
    }
    
    public int [] IntArray(int n) {
        final int [] Array = new int [n];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = nextInt();
        }
        return Array;
    }
    public int [][] IntArray(int n , int m) {
        final int [][] Array = new int [n][m];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = IntArray(m);
        }
        return Array;
    }   
    public long [] LongArray(int n) {
        final long [] Array = new long [n];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = nextLong();
        }
        return Array;
    }
    public long [][] LongArray(int n , int m) {
        final long [][] Array = new long [n][m];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = LongArray(m);
        }
        return Array;
    }
    public String [] StringArray(int n) {
        final String [] Array = new String [n];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = next();
        }
        return Array;
    }
    public char [] CharArray(int n) {
        final char [] Array = new char[n];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = next().charAt(0);
        }
        return Array;
    }
    public char [][] CharArray(int n , int m) {
        final char [][] Array = new char [n][m];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = next().toCharArray();
        }
        return Array;
    }
    public char [][] CharArray2(int n , int m) {
        final char [][] Array = new char [n][m];
        for(int i = 0 ; i < n ; i ++ ) {
            for(int j = 0 ; j < m ; j ++ ) {
                Array[i][j] = next().charAt(0);
            }
        }
        return Array;
    }
    public List<Integer> [] Graph(int n) {
        @SuppressWarnings("unchecked")
        List<Integer> [] G = new ArrayList[n];
        for(int i = 0 ; i < n ; i ++ ) {
            G[i] = new ArrayList<>();
        }
        return G ;
    }
}