I am writing a code based on some formulas;but my if statement does not seem to work(line 33)

W = int(input('Enter weight:'))

b = [1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0]
AR = [1, 2, 3, 4, 5]
T = [50.99238, 50.05062, 49.07943, 48.05919, 47.00952, 45.92061, 44.79246, 43.62507,       42.42825, 41.18238, 39.90708, 38.60235, 37.24857, 35.86536, 34.4331, 32.97141, 31.48029, 29.94012, 28.37052, 26.76168, 25.1136]
CL = [1.0]
CD = [0.5]
clmax = 2
n = 0
z = 0
while b[n] < 2.1 :

    while AR[z]< 5.1:
        cl = CL[n]
        cd = CD[z]
        s = ((b[n]*b[n])/AR[z])                                
        V = ((2*W*9.81)/(1.2*s*clmax) ** 0.5)*1.1
        vlof = V/1.41
        Vlof = round(vlof)
        D = 0.5*cd*1.2*Vlof*Vlof*s
        L = 0.5*cl*1.2*Vlof*Vlof*s
        a = (9.81/W)*(T[Vlof]-D-O.O5(W-L))
        Sg = (V*V)/(2*a)
        if Sg <= 30:
            print('IT WILL TAKEOFF')
        else:
            print('It will NOT takeoff')
        t/c = int(input('t/c ratio is:'))
        l = int(input('Taper ratio is:'))
        f = 0.005(1+1.5*((l-0.6)**2))
        e = (1/((1+0.12*V*V*0.003*0.003)(1+(0.142+(f*AR[z]*(10*t/c)**0.33)
            +(0.1/(4+AR[z])**0.8))
        if z <= 5:                              # line 33 #
                                     z +=1
        else :
                                     break

   n+=1                

OUTPUT:

  File "<ipython-input-49-d7d52927efb2>", line 33
    if z <= 5:
         ^
SyntaxError: invalid syntax

This is a code which should tell me whether my aircraft will takeoff or not (on the input of a weight) I cannot seem to understand the reason why is this syntax invalid ?