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f, ax = plt.subplots(figsize=(12, 4))
ax.set(xscale="log")
plt.plot(x, y)
plt.grid(which="both", axis='both')
_ = plt.xticks([20,50,100,200,500,1000,2000,5000,10000,20000],
["20", "50", "100", "200", "500", "1K", "2K", "5K", "10K", "20K"])