There are 100 numbers 1, 2, 3, ..., 99, 100 written on the blackboard. Erase 2 numbers arbitrarily each time, and then write the sum of these 2 numbers minus 1. After several times, only Next one number, what is this number.
黑板上写着1，2，3，…，99，100共100个数，每次任意擦去2个数，再写上这2个数的和减1，经过若干次后，黑板上只剩下1个数，这个数是多少．
<gadget id="calculator">1 + 100</gadget>
<output>101</output>

<gadget id="calculator">100 / 2</gadget>
<output>50</output>

<gadget id="calculator">101 * 50</gadget>
<output>5_050</output>

<gadget id="calculator">5_050 - 99</gadget>
<output>4_951</output>

<result>4_951</result>