#include <cstdio>
#include <iostream>
#include <fstream>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <cstring>
#include <string>
#include <ctime>
#include <cassert>
#include <utility>

using namespace std;

double LIMIT;

struct ellipse {
    double cx, cy, rx, ry;
    
    void read() {
        cin >> cx >> cy >> rx >> ry;
    }
    
    bool isInside(double x, double y) {
        double v1 = (x - cx) * ry;
        double v2 = (y - cy) * rx;
        double v3 = rx * ry;
        return v1 * v1 + v2 * v2 <= v3 * v3;
    }
} e[3];

int isInAnEllipse(double x, double y, double len) {
    double pts[4][2] = {
            { x, y },
            { x, y + len },
            { x + len, y },
            { x + len, y + len }
        };
    bool any = false;
    for(int i = 0; i < 3; i++) {
        bool ok = true;
        for(int j = 0; j < 4; j++) {
            ok &= e[i].isInside(pts[j][0], pts[j][1]);
            any |= e[i].isInside(pts[j][0], pts[j][1]);
        }
        if(ok)
            return 1;
    }
    if(!any)
        return -1;
    return 0;
}

double go(double x, double y, double len) {
    if(len < LIMIT)
        return 0.0;
    int aux = isInAnEllipse(x, y, len);
    if(aux == 1)
        return len * len;
    if(aux == -1)
        return 0.0;
    
    double pts[4][2] = {
            { x, y },
            { x, y + len / 2 },
            { x + len / 2, y },
            { x + len / 2, y + len / 2 }
        };
    double ret = 0.0;
    for(int i = 0; i < 4; i++)
        ret += go(pts[i][0], pts[i][1], len / 2);
    return ret;
}

int main() {
//	freopen("date.in", "r", stdin);
//	freopen("date.out","w", stdout);
	
	for(int i = 0; i < 3; i++)
        e[i].read();
	
	LIMIT = 1e-4;
	double ans = 0;
	for(int i = -50; i <= 50; i++)
        for(int j = -50; j <= 50; j++)
            ans += go(i, j, 1.0);
	cout << ans << endl;
	
	return 0;
}