C++ :

#include <bits/stdc++.h>
using namespace std;
int main()
{
	int a[20],b[20],c[20]={7,9,10,5,8,4,2,1,6,3,7,9,10,5,8,4,2},i,sum=0;
	char d[20]={'1','0','X','9','8','7','6','5','4','3','2'};
	for(i=0;i<17;i++)
	{
		cin>>a[i];
		sum+=a[i]*c[i];
	}
	sum%=11;
	cout<<d[sum]<<endl;
	return 0;
}