#define _USE_MATH_DEFINES #define _CRT_SECURE_NO_DEPRECATE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long long ll; typedef unsigned long long ull; typedef pair Pii; typedef pair Pll; #define FOR(i,n) for(int i = 0; i < (n); i++) #define sz(c) ((int)(c).size()) #define ten(x) ((int)1e##x) template static inline int getchar_unlocked(void) { return getchar(); } template static inline void putchar_unlocked(int c) { putchar(c); } #define mygc(c) (c)=getchar_unlocked() #define mypc(c) putchar_unlocked(c) void reader(int& x) { int k, m = 0; x = 0; for (;;) { mygc(k); if (k == '-') { m = 1; break; }if ('0' <= k&&k <= '9') { x = k - '0'; break; } }for (;;) { mygc(k); if (k<'0' || k>'9')break; x = x * 10 + k - '0'; }if (m) x = -x; } void reader(ll& x) { int k, m = 0; x = 0; for (;;) { mygc(k); if (k == '-') { m = 1; break; }if ('0' <= k&&k <= '9') { x = k - '0'; break; } }for (;;) { mygc(k); if (k<'0' || k>'9')break; x = x * 10 + k - '0'; }if (m) x = -x; } int reader(char c[]) { int i, s = 0; for (;;) { mygc(i); if (i != ' '&&i != '\n'&&i != '\r'&&i != '\t'&&i != EOF) break; }c[s++] = i; for (;;) { mygc(i); if (i == ' ' || i == '\n' || i == '\r' || i == '\t' || i == EOF) break; c[s++] = i; }c[s] = '\0'; return s; } template void reader(T& x, S& y) { reader(x); reader(y); } template void reader(T& x, S& y, U& z) { reader(x); reader(y); reader(z); } template void reader(T& x, S& y, U& z, V & w) { reader(x); reader(y); reader(z); reader(w); } void writer(int x, char c) { int s = 0, m = 0; char f[10]; if (x<0)m = 1, x = -x; while (x)f[s++] = x % 10, x /= 10; if (!s)f[s++] = 0; if (m)mypc('-'); while (s--)mypc(f[s] + '0'); mypc(c); } void writer(ll x, char c) { int s = 0, m = 0; char f[20]; if (x<0)m = 1, x = -x; while (x)f[s++] = x % 10, x /= 10; if (!s)f[s++] = 0; if (m)mypc('-'); while (s--)mypc(f[s] + '0'); mypc(c); } void writer(const char c[]) { int i; for (i = 0; c[i] != '\0'; i++)mypc(c[i]); } void writer(const char x[], char c) { int i; for (i = 0; x[i] != '\0'; i++)mypc(x[i]); mypc(c); } template void writerLn(T x) { writer(x, '\n'); } template void writerLn(T x, S y) { writer(x, ' '); writer(y, '\n'); } template void writerLn(T x, S y, U z) { writer(x, ' '); writer(y, ' '); writer(z, '\n'); } template void writerArr(T x[], int n) { if (!n) { mypc('\n'); return; }FOR(i, n - 1)writer(x[i], ' '); writer(x[n - 1], '\n'); } ll mod_pow(ll a, ll n, ll mod) { ll ret = 1; ll p = a % mod; while (n) { if (n & 1) ret = ret * p % mod; p = p * p % mod; n >>= 1; } return ret; } template T extgcd(T a, T b, T& x, T& y) { for (T u = y = 1, v = x = 0; a;) { T q = b / a; swap(x -= q * u, u); swap(y -= q * v, v); swap(b -= q * a, a); } return b; } template T mod_inv(T a, T m) { T x, y; extgcd(a, m, x, y); return (m + x % m) % m; } template T gcd(T a, T b) { return b ? gcd(b, a % b) : a; } int solve(int d, int a, int b, int c) { if (a > c) swap(a, c); int pr = 0; if (a == c) a = max(0, a - d), pr++; if (a == c) return -1; // a != c if (b < a || c < b) return pr; if (d == 0) { return -1; } int ans1 = 0; if (a == 0) ans1 = 2 * ten(9); else ans1 = (b - a) / d + 1; int ans2 = 0; int da = a == b; a -= da * d; a = max(0, a); int dc = (c - b) / d + 1; dc = max(0, dc); c -= dc * d; c = max(0, c); if (a == c) ans2++, a = max(0, a - d); if (a == b || b == c || c == a) ans2 = 2 * ten(9); else ans2 += da + dc; int ans = min(ans1, ans2) + pr; if (ans >= ten(9) * 2) ans = -1; return ans; } int main() { int n; int a, b, c; reader(n, a, b, c); int ans = solve(n, a, b, c); cout << ans << endl; }