import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.NoSuchElementException;

public class Main {

	public static void main(String[] args) {
		new Main().run();
	}
	
	long gcd(long a,long b) {
		return a==0?b:gcd(b%a,a);
	}
	
	long h(long a,long b) {
		return (gcd(a,b)+(a+1)*(b+1))/2+1;
	}
	
	long g(long d,long x,long y) {
		if (x<0||y<0||d<0) return 0;
		if (x+y<=d) return (x+1)*(y+1);
		return (x+1)*(y+1)-h(x+y-d,x+y-d)+x+y-d+1;
	}
	
	long f(long x1,long y1,long d,long x2,long y2) {
		x2=Math.min(x2, x1+d);
		y2=Math.min(y2, y1+d);
		return g(d,x2-x1,y2-y1);
	}
	
	long f_brute(long x1,long y1,long d,long x2,long y2) {
		long ret=0;
		for (long x=x1;x<=x1+d;++x) {
			for (long y=y1;y<=y1+d;++y) {
				long dx=x-x1;
				long dy=y-y1;
				if (dx+dy>d) continue;
				if (x<=x2&&y<=y2) ++ret;
			}
		}
		return ret;
	}
	
	void run() {
		FastScanner sc=new FastScanner();
		long x1=sc.nextLong();
		long y1=sc.nextLong();
		long x2=sc.nextLong();
		long y2=sc.nextLong();
		long d=sc.nextLong();
		x2=Math.min(x2, +d);
		y2=Math.min(y2, +d);
		x1=Math.max(x1, -d);
		y1=Math.max(y1, -d);
		long ans=0;
		if (x1<=0&&0<=x2&&y1<=0&&0<=y2)++ans;
		ans+=f(Math.max(+x1, 1),Math.max(0,+y1),d-(Math.max(+x1, 1)+Math.max(0,+y1)),+x2,+y2);//第1象限
		ans+=f(Math.max(-x2, 0),Math.max(1,+y1),d-(Math.max(-x2, 0)+Math.max(1,+y1)),-x1,+y2);//第2象限
		ans+=f(Math.max(-x2, 1),Math.max(0,-y2),d-(Math.max(-x2, 1)+Math.max(0,-y2)),-x1,-y1);//第3象限
		ans+=f(Math.max(+x1, 0),Math.max(1,-y2),d-(Math.max(+x1, 0)+Math.max(1,-y2)),+x2,-y1);//第4象限
		System.out.println(ans);
	}
	
	void tr(Object...objects) {System.out.println(Arrays.deepToString(objects));}
}

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;}
    public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; 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() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    
    public double nextDouble() { return Double.parseDouble(next());}
}