#include <stdio.h>

int main(void) {
	char s[256] = "1998979695949392919099888786858483828180897877767574737271707968676665646362616069585756555453525150594847464544434241404938373635343332313039282726252423222120291817161514131211101987654321";
	int k[256] = {0},n,i,a;
	scanf("%d",&n);
	for(i = 0;i < 190;i++){
		a = s[i] - 48;
		a*=n;
		a+=k[i];
		k[i] = a%10;
		k[i+1]+=((a/10)%10);
		k[i+2]+=((a/100)%10);
	}
	if(k[191] != 0){printf("%d%d.",k[191],k[190]);}
	else if(k[190] != 0){printf("%d.",k[190]);}
	else{printf("0.");}
	for(i = 189;i >= 0;i--){printf("%d",k[i]);}
	printf("\n");
	return 0;
}