#include<iostream>
#include<vector>
#include<map>
#include<cmath>
#include<string>
#include<fstream>
#include<algorithm>
#include<unordered_set>
#include<iomanip>
#include<set>

using namespace std;

int main() {
    long long A, B, C, D;
    long long ans = (long long)0;
    /*for (int A = 1; A <= 10; ++A) {
        for (int B = 1; B <= 10; ++B) {
            for (int C = 4; C <= 10; ++C) {
                for (int D = 4; D <= 10; ++D) {
                    cout << A << " " << B << " " << C << " " << D << endl;
                }
            }
        }
    }*/
    cin >> A >> B >> C >> D;
    for (long long a = (long long)1; a <= D / 2; ++a) {
        for (long long b = a; a + b + a + b >= C && a + b + a + b <= D; ++b) {
            if (a * b >= A && a * b <= B) {
                ++ans;
                //cout << a << " " << b << endl;
            }
        }
    }
    cout << ans;
    return 0;
}