#include <cstdio>

void main()

{

double length;

double l[300];

l[1] = 1.0/2;

int i;

for (i = 2;; ++i)

{

l[i] = l[i-1] + 1.0/(i+1);

if (l[i] >= 5.20)

break;

}

while (scanf("%lf", &length), length > 0)

{

for (i = 1;; ++i)

{

if (l[i] >= length) break;

}

printf("%d card(s)\n",i);

}

}