double v0;
        cin >> v0;
        double vx, vy, m0;
        cin >> vx >> vy >> m0;
        double dt;
        int x1 = 0;
        int y11 = 301;
        while (m > 0.2 * m0){
            int i = 0;
            dt = 1 / vx;
            x[i] = x1 + vx * dt;
            y[i] = y11 + vy * dt
            m -= (delta m)/ (delta t) * dt;
            vx += (delta m)/ (delta t) * dt / m * vx;
            vy += (delta m)/ (delta t) * dt / m * vx - 9.8 * dt;
            x1 = x[i];
            y11 = y[i];
            i++;
        }