#include <stdio.h>

int n;
double dp[1000001][7];

int main() {
	scanf("%d", &n);
	
	dp[0][0] = 1;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j <= 6; j++) {
			dp[i + 1][j] = dp[i][j] * j / 6.0;
			if (j < 6) {
				dp[i + 1][j + 1] = dp[i][j] * (6.0 - j) / 6.0;
			}
		}
	}

	printf("%.14f\n", dp[n][6]);
	return 0;
}