#include <iostream>
#include <math.h>
using namespace std;
int main() {
long long collatz(long long),n,test,k,count=0;
for(n=2;n<pow(10,7);n++)
{
k=1;
test=n;
while(collatz(test)!=1)
{
test=collatz(test);
k++;
}
if(k%2==1)
count++;
}
cout<<count;
return 0;
}
long long collatz(long long x)
{
return (x%2==0) ? x/2 : 3*x+1;
}
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