/*
 * ELEVTRBL.cpp
 *
 *  Created on: Jun 15, 2014
 *      Author: Arpit Bhayani
 */

#include <queue>
#include <cstdio>
#include <cstdlib>
#include <iostream>

using namespace std;

#define DEBUG 0
#define gc getchar
#define ll long long

void scanint(ll int &x) {
    register ll int c = gc();
    x = 0;
    for (; (c < 48 || c > 57); c = gc())
        ;
    for (; c > 47 && c < 58; c = gc()) {
        x = (x << 1) + (x << 3) + c - 48;
    }
}

int readline(char * str) {

    int i = 0;
    char ch;
    while ((ch = getchar()) != '\n') {
        str[i++] = ch;
    }
    str[i] = '\0';
    return i;
}

int visited[1000010];

int main(int argc, char * argv[]) {

    int f, s, g, u, d;
    cin >> f >> s >> g >> u >> d;
    queue<pair<int, int> > q;

    q.push(make_pair(s, 0));

    while (!q.empty()) {

        int curfloor = q.front().first;
        int curlevel = q.front().second;
        q.pop();

        if (visited[curfloor] == 1) {
            continue;
        }

        visited[curfloor] = 1;

        if (curfloor == g) {
            cout << curlevel << endl;
            return 0;
        }

        if (curfloor + u <= f) {
            q.push(make_pair(curfloor + u, curlevel + 1));
        }

        if (curfloor - d > 0) {
            q.push(make_pair(curfloor - d, curlevel + 1));
        }

    }

    cout << "use the stairs" << endl;

    return 0;
}