#include <cstdio>
using namespace std;
long long n,i,j,x,y,p,q,r;
int main()
{
freopen("jumatate1.in","r",stdin);
freopen("jumatate1.out","w",stdout);
scanf("%lld\n",&n);
p=q=1;
while (n/q>0)
{
p*=10;
q*=100;
}
x=n/p; y=n%p; r=x%y;
while(r)
{
x=y;
y=r;
r=x%y;
}
printf("%lld\n",y);
return 0;
}