import math
euler = 0
factorial = 1
x = 0
while 1./factorial > 1e-9:
    factorial = 1
    j = 1
    while j <= x:
        factorial *= j
        j += 1
    euler += 1./factorial
    x += 1
print ('math value : e = ',math.exp(1),' value from serie : e = ',euler)