#include <stdio.h> _int64 fact(int x){ _int64 s=1; int i; for(i=2;i<=x;++i){ s=s*i; } return s; } int main() { int i, n,flag; _int64 sum; while( scanf("%d", &n) != EOF){ sum=0,flag=1; for(i=2;i<=n;++i){ if(i%2==0) flag=1; else flag=-1; sum += flag*fact(n)/fact(i); } printf("%I64d/n", sum); } return 0; }