UVA 12869

/*
Problem : UVA 12869
Idea : Very nice Problem. The value changes per 5 values.
*/

#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define EB emplace_back
#define MP make_pair
#define all(o) (o).begin(), (o).end()
#define mset(m,v) memset(m,v,sizeof(m))
#define fr(i,n) for(lli i=0;i<n;++i)
#define rep(i,a,b) for(lli i=a;i<=b;++i)
#define remin(a,b) (a=min((a),(b)))
#define remax(a,b) (a=max((a),(b)))
#define endl '\n'
typedef unsigned long long int lli;
typedef long double ld;
typedef pair< lli,lli > ii;
typedef vector<lli> vi;
typedef vector<ii> vii;
typedef vector<vi> graph;
lli MOD=1000000007;long double EPS=1e-9;

lli getcnt(lli x){
    return x/5;
}

bool solve(){
    lli lo,hi;
    cin>>lo>>hi;
    if(lo==0)return 0;
    lli cnt1=getcnt(lo);
    lli cnt2=getcnt(hi);
    cout<<cnt2+1-cnt1<<endl;
    return 1;
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    //freopen("in.txt","r",stdin);
    //freopen("out.txt","w",stdout);
    //pre();
    int t=1;
    //cin>>t;
    for(int i=1;solve();i++){
        //cout<<"Case #"<<i<<": ";

    }
}