# include <iostream>
using namespace std;
int num[110],n,m;
unsigned long long k;
int main(){
	cin >> n >> m >> k;
	num[1] = n%10,num[2] = m%10;
	for(int i = 3; i <= 100; i++) num[i] = (num[i-1]*num[i-2])%10;
	k %= 100;
	if(k != 0) cout << num[k];
	else cout << num[100];
}