#include using namespace std; /*{{{*/ //template #define rep(i,n) for(int i=0;i<(int)(n);i++) #define rrep(i,n) for(int i=(n)-1;i>=0;i--) constexpr int INF = numeric_limits::max()/2; constexpr long long LINF = numeric_limits::max()/3; #define pb push_back #define eb emplace_back #define fi first #define se second #define all(v) (v).begin(),(v).end() #define sz(x) (int)(x).size() #define debug(x) cerr<<#x<<":"< ostream& operator<<(ostream& os,const vector& vec){ os << "["; for(const auto& v : vec){ os << v << ","; } os << "]"; return os; } template ostream& operator<<(ostream& os, const map& mp){ os << "{"; for(auto& p : mp){ os << p << ","; } os << "}"; return os; } template ostream& operator<<(ostream& os,const pair& p){ os << "(" << p.first << ","<< p.second <<")"; return os; } template ostream& operator<<(ostream& os,const set& st){ os<<"{"; for(T v:st) os< inline void chmax(T &x,U y){ if(y>x) x = y; } template inline void chmin(T &x,U y){ if(y; using vi = std::vector; typedef vector vvi; ll gcd(ll a,ll b){ if(b==0) return a; else return gcd(b,a%b); } constexpr ll TEN(int n) { return (n == 0) ? 1 : 10 * TEN(n - 1); } //constexpr double eps = 1e-14; constexpr double eps = 1e-10; constexpr ll mod = 1e9+7; const int dx[]={1,0,-1,0} ,dy[] = {0,1,0,-1}; /*}}}*/ ll d; ll minimize(vector h){ if(h[1] == 0) return LINF; ll ret = 0; if(h[1] == h[2]){ h[1] = max(h[1]-d,0); ret++; } //cout << h << endl; if(h[0] < h[1]) return ret; return (h[0]-(h[1]-1)+d-1)/d + ret; } ll maximize(vector h){ if(h[0] == 0) return LINF; ll ret = 0; if(h[0] < h[1]){ ll t = (h[1] - (h[0] - 1) + d - 1) / d; h[1] = h[1] - t * d; ret += t; } if(h[0] < h[2]){ ll t = (h[2] - (h[0] - 1) + d - 1) / d; h[2] = h[2] - t * d; ret += t; } if(h[1] == h[2]){ h[1] = max(h[1]-d,0); ret++; } if(h[1] == h[2]){ return LINF; } return ret; } int main(){ cin >> d; vector h(3); rep(i,3) cin >> h[i]; swap(h[0],h[1]); if(h[1] > h[2]) swap(h[1],h[2]); //cout << minimize(h) << endl; //cout << maximize(h) << endl; ll ans = min(minimize(h), maximize(h)); if(ans == LINF){ cout << -1 << endl; return 0; } cout << ans << endl; }