import numpy as np

def mystery(x):
    p1 = np.exp(-(x + 5)**2 / (2 * 0.5**2))
    p2 = 0.7 * np.exp(-(x - 5)**2 / (2 * 1.5**2))
    p3 = 0.5 * np.exp(-(x - 20)**2 / (2 * 0.2**2))
    return p1 + p2 + p3