#include <stdio.h>
int power(int a, int b)
{
int res = 1;
if (b == 0)
return 1;
for (int i = 0; i < b; i++)
res *= a;
return res;
}
int factorial(int x)
{
int res = 1;
for (int i = 1; i <= x; i++)
{
res *= i;
}
return res;
}
int main(void)
{
int sum = 0, n, k, res=0;
scanf("%d %d", &n, &k);
if (n>4)
for (int i = 0; i <= 4; i++)
sum += power(factorial(i), k);
else
for (int i = 0; i <= n; i++)
sum += power(factorial(i), k);
while (res == 0)
{
res = sum % 10;
sum /= 10;
}
printf("%d", res);
return 0;
}
