#include #define EPS 1e-9 #define INF 1070000000LL #define MOD 1000000007LL #define fir first #define foreach(it,X) for(auto it=(X).begin();it!=(X).end();it++) #define numa(x,a) for(auto x: a) #define ite iterator #define mp make_pair #define rep(i,n) rep2(i,0,n) #define rep2(i,m,n) for(int i=m;i<(n);i++) #define pb push_back #define pf push_front #define sec second #define sz(x) ((int)(x).size()) #define ALL( c ) (c).begin(), (c).end() #define gcd(a,b) __gcd(a,b) #define mem(x,n) memset(x,n,sizeof(x)) #define endl "\n" using namespace std; template void deploy(std::ostream &os, const TUPLE &tuple){} template void deploy(std::ostream &os, const TUPLE &t){ os << (POS == 0 ? "" : ", ") << get(t); deploy(os, t); } template std::ostream& operator<<(std::ostream &os, std::pair &p){ os << "(" << p.first <<", " << p.second <<")";return os; } template std::ostream& operator<<(std::ostream &os, std::vector &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "}" : ", "); return os; } template std::ostream& operator<<(std::ostream &os, std::set &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "}" : ", "); return os; } template std::ostream& operator<<(std::ostream &os, std::map &mp){ int remain = mp.size(); os << "{"; for(auto e: mp) os << "(" << e.first << " -> " << e.second << ")" << (--remain == 0 ? "}" : ", "); return os; } #define DEBUG1(var0) { std::cerr << (#var0) << "=" << (var0) << endl; } #define DEBUG2(var0, var1) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG1(var1); } #define DEBUG3(var0, var1, var2) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG2(var1,var2); } #define DEBUG4(var0, var1, var2, var3) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG3(var1,var2,var3); } using ll = long long; ll d; void cut(int &x){ x -= d; if (x < 0) { x = 0; } } int cut(int x, int &y){ int z = (y-x) / d + 1; y -= z * d; if (y < 0) { y = 0; } return z; } int go(vector nums, int cnt){ if (nums[0] > nums[2]) { swap(nums[0],nums[2]); } if (nums[0] == nums[2]) { if (nums[0] == 0) { return INT_MAX; } cut(nums[0]); cnt += 1; } if (nums[1] < nums[0]) { return cnt; } if (nums[1] > nums[2]) { return cnt; } //num[0] > nums[1] int a = INT_MAX; if (nums[0] == nums[1]) { if (nums[0] == 0) { return INT_MAX; }else{ return 1; } }else if (nums[0] < nums[1]){ int tmp = nums[1]; int z = cut(nums[0], nums[1]); a = go(nums, cnt + z); nums[1] = tmp; } if (nums[1] == nums[2]) { if (nums[1] == 0) { return INT_MAX; }else{ int tmp = nums[2]; int z = cut(nums[1], nums[2]); a = min(a, go(nums, cnt + z)); nums[2] = tmp; } }else if (nums[1] < nums[2]) { int tmp = nums[2]; int z = cut(nums[1], nums[2]); a = min(a, go(nums, cnt + z)); nums[2] = tmp; } return a; } int main() { cin.tie(0); ios_base::sync_with_stdio(0); vector nums(3); cin >> d; rep(i,3){ cin >> nums[i]; } if (d == 0) { cout << -1 << endl; return 0; } int ans = go(nums, 0); if (ans == INT_MAX) { cout << -1 << endl; }else{ cout << ans << endl; } return 0; }