A. Alyona and Numbers

 1 import java.util.ArrayList;
 2 import java.util.Scanner;
 3 
 4 public class Main {
 5     public static void main(String[] args) {
 6         Scanner io = new Scanner(System.in);
 7         int n = io.nextInt(), m = io.nextInt();
 8         long ans = 0;
 9         for (int i = 1, y; i <= n; i++) {
10             y = 5 - (i % 5);
11             if (y == 0) y += 5;
12             if (y > m) continue;
13             ans += (m - y) / 5 + 1;
14         }
15         System.out.println(ans);
16     }
17 
18 
19 }