#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <string>
#include <vector>
#include <sstream>
#include <cmath>
#include <cstring>
#include <cstdio>
#include <ctime>
#include <cassert>
using namespace std;

const int N = 505;
int x, a, y, b, len;
pair<int, int> dp[N][N];

bool can(int w)
{
    for (int i = 0; i <= x; i++)
        for (int j = 0; j <= y; j++)
            dp[i][j] = make_pair(0, 0);

    for (int i = 0; i <= x; i++)
        for (int j = 0; j <= y; j++)
        {
            int rows = dp[i][j].first;
            int rem = dp[i][j].second;

            int rem1 = rem + a;
            int rows1 = rows + (rem1 >= w);
            if (rem1 >= w)
                rem1 = 0;
            dp[i + 1][j] = max(dp[i + 1][j], make_pair(rows1, rem1));

            int rem2 = rem + b;
            int rows2 = rows + (rem2 >= w);
            if (rem2 >= w)
                rem2 = 0;
            dp[i][j + 1] = max(dp[i][j + 1], make_pair(rows2, rem2));
        }


    for (int i = 0; i <= x; i++)
        for (int j = 0; j <= y; j++)
            if (dp[i][j].first >= len)
                return true;
    return false;
}

bool solve()
{
    if (scanf("%d%d%d%d%d", &x, &a, &y, &b, &len) != 5)
        return false;

    int l = 0;
    int r = (x * a + y * b) / len + 1;
    while (r - l > 1)
    {
        int m = (l + r) / 2;
        if (can(m))
            l = m;
        else
            r = m;
    }

    printf("%d\n", l);

    return true;
}

int main()
{
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
#endif

    while (solve()) {}


    return 0;
}