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Welcome to my column.”The daily blue bridge”, the main role of this column is to share with you in recent years blue bridge cup provincial competition and the final and other real questions, analysis of the existing algorithm ideas, data structure and other content, to help you learn more knowledge and technology!

The thirty-ninth step

Xiao Ming has just seen the movie The 39th Step. When he is leaving the cinema, he counts the number of steps in front of the auditorium. It happens to be 39.

If I could only take one or two steps at a time, starting with my left foot, then alternating between left and right, and ending with my right foot, which is an even number of steps, how many different ways could I take up 39 steps?

Please take advantage of the computer to help Xiao Ming find the answer.

An integer is required to submit

Note: do not submit the solution process, or other supporting text

Their thinking: