用对数
#include <iostream>
#include <iostream>
#include <cmath>
using namespace std;
int main()
{
int y;
while(cin>>y&&y)
{
int i;
double sum=0.0;
int t=(y-1960)/10+2;
t=1<<t;
for(i=1;;i++)
{
if(t-sum>=1e-8)
{
sum+=(log(i)/log(2.));
// cout<<log(i)<<" "<<sum<<endl;
}
else
{
break;
}
}
cout<<i-2<<endl;
}
return 0;
}