import java.util.*;
import java.lang.*;
import java.io.*;
 
 
class f
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		Scanner sc=new Scanner(System.in);
 
		int n,s;
		n=sc.nextInt();
		s=sc.nextInt();
		int maxx=-1;
		for(int i=0;i<n;i++)
		{
			int d,c;
			d=sc.nextInt();
			c=sc.nextInt();
			if(100*d+c<=s*100 && (-100*d-c+s*100)%100>maxx)
				maxx=(-100*d-c+s*100)%100;
		}
		System.out.println(maxx);
	}
}

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