#include<bits/stdc++.h>
using namespace std;
int main()
{
	double a,d;
	int b,c;
	cin>>a;
	a*=10;
	c=a;
	while(c)
	{
		b*=10;
		b+=c%10; 
		c/=10;
	}
	for(d=b;d>=10;)
	{
		d/=10;
	}
	cout<<d<<endl;
	return 0;
}