#include <iostream>
#include <assert.h>
using namespace std;

int main() {
    //freopen("sin.txt", "r", stdin);
    //freopen("sout.out", "w", stdout);
    int t;
    cin >> t;
    assert(t > 0 && t <= 1000);
    while(t--) {
        int n, k;
        cin >> n >> k;
        assert(n > 1 && n <= 1000);
        assert(k > 0 && k <= n);
        int ans = 0;
        for(int i = k; i < n; i++)
            if(!(i%5)) ans++;
        cout << ans << "\n";
    }
}