import java.awt.geom.Point2D; import java.io.*; import java.math.*; import java.util.*; import java.util.Map.*; class Main { public static void main(String[] args) { //FastScanner sc = new FastScanner(); Scanner sc = new Scanner(System.in); int sum = 0; int max = 0; int min = 2 << 27; for(int i = 0; i < 6; i++) { int v = sc.nextInt(); sum += v; max = Math.max(v, max); min = Math.min(v, min); } sum -= max; sum -= min; String vv = Double.toString((sum / 4.0)); vv += "0000000"; for(int i = 0; i < vv.length(); i++) { if(vv.charAt(i) == '.') { vv = vv.substring(0,i+3); } } System.out.println(vv); } static class FastScanner { private final InputStream in = System.in; private final byte[] buffer = new byte[1024]; private int ptr = 0; private int buflen = 0; private boolean hasNextByte() { if (ptr < buflen) { return true; }else{ ptr = 0; try { buflen = in.read(buffer); } catch (IOException e) { e.printStackTrace(); } if (buflen <= 0) { return false; } } return true; } private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;} private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;} private void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;} public boolean hasNext() { skipUnprintable(); return hasNextByte();} public String next() { if (!hasNext()) throw new NoSuchElementException(); StringBuilder sb = new StringBuilder(); int b = readByte(); while(isPrintableChar(b)) { sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } public long nextLong() { if (!hasNext()) throw new NoSuchElementException(); long n = 0; boolean minus = false; int b = readByte(); if (b == '-') { minus = true; b = readByte(); } if (b < '0' || '9' < b) { throw new NumberFormatException(); } while(true){ if ('0' <= b && b <= '9') { n *= 10; n += b - '0'; }else if(b == -1 || !isPrintableChar(b)){ return minus ? -n : n; }else{ throw new NumberFormatException(); } b = readByte(); } } public int nextInt() { if (!hasNext()) throw new NoSuchElementException(); int n = 0; boolean minus = false; int b = readByte(); if (b == '-') { minus = true; b = readByte(); } if (b < '0' || '9' < b) { throw new NumberFormatException(); } while(true){ if ('0' <= b && b <= '9') { n *= 10; n += b - '0'; }else if(b == -1 || !isPrintableChar(b)){ return minus ? -n : n; }else{ throw new NumberFormatException(); } b = readByte(); } } } }