import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    static long X, Y, firstZ;
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());
        X = Integer.parseInt(st.nextToken());
        Y = Integer.parseInt(st.nextToken());
        long t = 0;
        firstZ = (Y)*100/X;
        if(firstZ >= 99){
            System.out.println(-1);
        } else{
            binarySearch(1,X);
        }
    }
    static void binarySearch(long start, long end){
        long mid = 0, Z = 0;
        while(start <= end ){
            mid = (start + end) / 2;
            Z = (Y + mid) * 100 / (X+mid);

            if(Z > firstZ){
                end = mid - 1;
            } else {
                start = mid+1;
            }
        }
        System.out.println(start);
    }
}