import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


long[] A;

long brute() {
  long ret;
  foreach (x0; 0 .. min(A[0], A[1], A[2]) + 1) {
    foreach (x1; 0 .. min(A[1] - x0, A[2] - x0, A[3]) + 1) {
      foreach (x2; 0 .. min(A[2] - x0 - x1, A[3] - x1, A[4]) + 1) {
        foreach (x3; 0 .. min(A[3] - x1 - x2, A[4] - x2, A[0] - x0) + 1) {
          const x4 = min(A[4] - x2 - x3, A[0] - x3 - x0, A[1] - x0 - x1);
          chmax(ret, x0 + x1 + x2 + x3 + x4);
        }
      }
    }
  }
  return ret;
}

bool check(long t) {
  /*
    x[i] >= 0
    \sum_i x[i] = t
    A[i] - t + x[i] + x[j] >= 0
  */
  auto xs = new long[5];
  // 0
  foreach (i; 0 .. 5) {
    xs[i] = 0;
    foreach (j; 0 .. 4) {
      xs[(i + j + 1) % 5] = max(t - A[(i + j) % 5] - xs[(i + j) % 5], 0);
    }
    if (xs[(i + 4) % 5] + xs[i] >= t - A[(i + 4) % 5]) {
      if (xs.sum <= t) {
        return true;
      }
    }
  }
  // 1
  foreach (i; 0 .. 5) {
    foreach (s; -10 .. +10 + 1) {
      xs[i] = ((t - A[i]) - (t - A[(i + 1) % 5]) + (t - A[(i + 2) % 5]) - (t - A[(i + 3) % 5]) + (t - A[(i + 4) % 5])) / 2 + s;
      if (xs[i] >= 0) {
        foreach (j; 0 .. 4) {
          xs[(i + j + 1) % 5] = max(t - A[(i + j) % 5] - xs[(i + j) % 5], 0);
        }
        if (xs[(i + 4) % 5] + xs[i] >= t - A[(i + 4) % 5]) {
          if (xs.sum <= t) {
            return true;
          }
        }
      }
    }
  }
  return false;
}

void main() {
  try {
    for (; ; ) {
      A = new long[5];
      foreach (i; 0 .. 5) {
        A[i] = readLong();
      }
      
      long lo = 0, hi = A.sum / 3 + 1;
      for (; lo + 1 < hi; ) {
        const mid = (lo + hi) / 2;
        (check(mid) ? lo : hi) = mid;
      }
      writeln(lo);
      
      debug {
        if (A.maxElement <= 100) {
          const brt = brute();
          writeln("brt = ", brt);
          assert(brt == lo);
        }
      }
    }
  } catch (EOFException e) {
  }
}