#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int, int>
const int INF = 1LL << 62;
int count(int x, int y, int z) {
if (y <= 0) {
return 0;
}
if (x >= y) {
return 1;
}
if (x <= z) {
return INF;
}
int lo = 0;
int hi = 200000000LL;
while (lo + 1 < hi) {
int mid = (lo + hi) / 2;
bool success = ((y - mid * x + mid * z - z) <= 0);
if (success) {
hi = mid;
} else {
lo = mid;
}
}
return hi;
}
int32_t main() {
cin.tie(0)->sync_with_stdio(0);
int atk, xl, yl, xh, yh;
cin >> atk >> xl >> yl >> xh >> yh;
if (xl == 0 && yl == 0) {
cout << 0;
return 0;
}
int ans = INF;
for (int i = 0; i < 2; ++i) {
int d1 = count(2 * atk, xl, xh);
int x_last_life = xl - (d1 - 1) * (2 * atk) + (d1 - 1) * xh;
int d2;
if (x_last_life > atk) {
d2 = count(2 * atk, yl + d1 * yh, yh);
} else {
int y_post = yl + (d1 - 1) * yh - atk;
if (y_post <= 0) {
d2 = 0;
} else {
d2 = count(2 * atk, y_post + yh, yh);
}
}
ans = min(ans, d1 + d2);
swap(xl, yl);
swap(xh, yh);
}
cout << ans;
}
