#include <stdio.h>


#define MAXL 1005

char s[MAXL];
int N[MAXL];

inline void mul( int A[], int B )
{
	int i, t = 0;
	for (i = 1; i <= A[0] || t; i++, t /= 10)
		A[i] = (t += A[i] * B) % 10;
	A[0] = i - 1;
}

inline void print( int A[] )
{
	int i = 0;
	for (i = A[0]; i; i--)
		printf("%d", A[i]);
	printf("\n");
}

int main()
{
	freopen("sarpe.in", "rt", stdin);
	freopen("sarpe.out", "wt", stdout);

	fgets(s, MAXL, stdin);
	int i;
	for (i = 0; s[i] && '0' <= s[i] && s[i] <= '9'; i++);
	for (i--; i >= 0; i--)
		N[ ++N[0] ] = s[i] - '0';

	if (N[0] == 1 && N[1] == 1)
	{
		printf("2\n");
		return 0;
	}
	mul(N, 12);

	N[1] -= 16;
	for (i = 1; i <= N[0] && N[i] < 0; i++)
		for (; N[i] < 0; )
			N[i] += 10,
			N[i + 1]--;
	for (; N[0] && !N[ N[0] ]; N[0]--);

	print(N);

	return 0;
}