import java.io.InputStream; import java.io.IOException; import java.io.PrintWriter; import java.util.ArrayDeque; import java.util.ArrayList; import java.util.Arrays; import java.util.BitSet; import java.util.Comparator; import java.util.Deque; import java.util.HashMap; import java.util.HashSet; import java.util.InputMismatchException; import java.util.Map; import java.util.PriorityQueue; import java.math.BigDecimal; import java.math.BigInteger; public class Main{ static final InputStream in=System.in; static final PrintWriter out=new PrintWriter(System.out); static final int INF=Integer.MAX_VALUE; static final long LINF=Long.MAX_VALUE/2; static int d; static int[] h; public static void main(String[] args) throws IOException{ InputReader ir=new InputReader(in); d=ir.nextInt(); h=ir.nextIntArray(3); out.println(dfs(0)); out.flush(); } public static int dfs(int dep){ if(check()) return dep; if(h[0]==0&&h[1]==0&&h[2]==0) return -1; int temp; int[] res=new int[3]; for(int i=0;i<3;i++){ if(h[i]!=0){ temp=h[i]; h[i]=Math.max(0,h[i]-d); res[i]=dfs(dep+1); h[i]=temp; } } int min=INF; for(int i=0;i<3;i++){ if(res[i]>0) min=Math.min(res[i],min); } return (min==INF)?-1:min; } public static boolean check(){ if(h[0]!=h[1]&&h[1]!=h[2]&&h[2]!=h[0]&&((h[1]>h[0]&&h[1]>h[2])||(h[1]=lenbuf){ curbuf= 0; try{ lenbuf=in.read(buffer); } catch (IOException e) { throw new InputMismatchException(); } if(lenbuf<=0) return -1; } return buffer[curbuf++]; } public boolean isSpaceChar(int c){return !(c>=33&&c<=126);} private int skip() {int b; while((b = readByte())!=-1&&isSpaceChar(b)); return b;} public String next() { int b=skip(); StringBuilder sb=new StringBuilder(); while(!isSpaceChar(b)){ sb.appendCodePoint(b); b=readByte(); } return sb.toString(); } public int nextInt() { int c=readByte(); while (isSpaceChar(c)) c=readByte(); boolean minus=false; if (c=='-') { minus=true; c=readByte(); } int res=0; do{ if(c<'0'||c>'9') throw new InputMismatchException(); res=res*10+c-'0'; c=readByte(); }while(!isSpaceChar(c)); return (minus)?-res:res; } public long nextLong() { int c=readByte(); while (isSpaceChar(c)) c=readByte(); boolean minus=false; if (c=='-') { minus=true; c=readByte(); } long res = 0; do{ if(c<'0'||c>'9') throw new InputMismatchException(); res=res*10+c-'0'; c=readByte(); }while(!isSpaceChar(c)); return (minus)?-res:res; } public double nextDouble(){return Double.parseDouble(next());} public BigInteger nextBigInteger(){return new BigInteger(next());} public int[] nextIntArray(int n){ int[] a=new int[n]; for(int i=0;i