t = [1,2,5,7,8,9,12,15,16,18,19,23,25,26,27,30]
a,b = 0,len(t)-1
e = 25

while a < b:
    m = int((a+b)/2)
    if t[m] < e:
        a = m+1
    else:
        b = m
if t[a] == e:
    print(a)
else:
    print('Non trouvé')