#include <stdio.h>

int main(void) {
    float cx[100], cy[100], cr[100], x[200], y[200], t;
    int n, i, j, k, dn;
    scanf("%d", &n);
    for (i = j = 0; i < n; i++) {
        scanf("%f%f%f", cx + i, cy + i, cr + i);
        x[j] = cx[i] - cr[i], y[j] = cy[i] - cr[i], j++;
        x[j] = cx[i] + cr[i], y[j] = cy[i] + cr[i], j++;
    }
    dn = j;
    for (i = 0; i < dn; i++)
        for (j = i + 1; j < dn; j++) {
            if (x[i] > x[j])
                t = x[i], x[i] = x[j], x[j] = t;
            if (y[i] > y[j])
                t = y[i], y[i] = y[j], y[j] = t;
        }
    t = 0;
    for (i = 1; i < dn; i++)
        for (j = 1; j < dn; j++)
            for (k = 0; k < n; k++)
                if (cx[k] - cr[k] <= x[i - 1] && x[i] <= cx[k] + cr[k] &&
                    cy[k] - cr[k] <= y[j - 1] && y[j] <= cy[k] + cr[k]) {
                    t += (y[j] - y[j - 1]) * (x[i] - x[i - 1]);
                    break;
                }
    printf("%.2f\n", t);
    return 0;
}