// No.2492 Knapsack Problem?
package main

import "fmt"

func main() {
	var n, w int
	fmt.Scan(&n, &w)

	vv, ww := 0, 0
	ans := -1
	for i := 0; i < n; i++ {
		fmt.Scan(&vv, &ww)
		if ww <= w {
			ans = max(ans, vv)
		}
	}
	fmt.Println(ans)
}