// yukicoder: No.220 世界のなんとか2
// bal4u 2019.8.25

#include <stdio.h>

typedef long long ll;

ll a[22] = {0,3};

int main()
{
	int i, P; ll b10, ans;

	scanf("%d", &P);
	if (P == 1) ans = 3;
	else {
		b10 = 1; for (i = 2; i <= P; i++) {
			b10 *= 10;
			a[i] = 9*(a[i-1]+1)+b10-1;
		}
		ans = a[P];
	}
	printf("%lld\n", ans);
	return 0;
}