#include <bits/stdc++.h>
using namespace std;

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(i,a,b) for (int i = (a); i < (b); i++)
#define RFOR(i,a,b) for (int i = (b)-1; i >= (a); i--)
#define REP(i,n) for (int i = 0; i < (n); i++)
#define RREP(i,n) for (int i = (n)-1; i >= 0; i--)
#define ALL(x) (x).begin(), (x).end()
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define MP(x,y) make_pair((x), (y))
#define MIN(a,b) (a < b ? a : b)
#define MAX(a,b) (a > b ? a : b)
#define AMIN(a,b) if(b < a) (a) = (b)
#define AMAX(a,b) if(b > a) (a) = (b)
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
#define bitcount(b) __builtin_popcount(b)
#define GCD(a,b) (__gcd(a,b))
#define GCD3(a,b,c) (GCD(GCD(a,b), c))
#define LCM(a,b) (a/GCD(a,b)*b)
#define LCM3(a,b,c) LCM(LCM(a,b),c)
#define MOD 1000000007
typedef long long ll;
// -------------------------------------

long X1, Y1, X2, Y2, D;
long Z;

long tri1(long n) {
  long k = (D - n);
  if (k >= 0) return k * k;
  return 0;
}

long f1(long n) {
  if (n >= 0) return tri1(n);
  else return Z - tri1(-n - 1);
}

long tri2(long n, long m) {
  long k = D - n - m - 1;
  if (k >= 0) return (k + 1) * k / 2;
  else return 0;
}

long f2(long n, long m) {
  if (n >= 0 && m >= 0) return tri2(n, m);
  if (n < 0 && m < 0) return Z - tri1(-n - 1) - tri1(-m - 1) + tri2(-n - 1, -m - 1);
  if (n < 0) return tri1(m) - tri2(-n - 1, m);
  else return tri1(n) - tri2(n, -m - 1);
}

int main() {
  cin >> X1 >> Y1 >> X2 >> Y2 >> D;

  Z = 2 * D * D + 2 * D + 1;

  long r = f1(X2);
  long t = f1(Y2);
  long l = f1(-X1);
  long b = f1(-Y1);

  long rt = f2(X2, Y2);
  long lt = f2(-X1, Y2);
  long lb = f2(-X1, -Y1);
  long rb = f2(X2, -Y1);

  cout << Z - r - t - l - b + rt + lt + lb + rb << endl;

  return 0;
}