#include<stdio.h>
#include<cmath>
long P;

int main()
{
    freopen("fact.in","r",stdin);
    freopen("fact.out","w",stdout);
    scanf("%ld",&P);
    long nr=0;
    long i=5;
    while(nr<P)
     {if(sqrt(i)==(int)sqrt(i))
          nr+=2;
         else nr++;
      i+=5;
     }
    if(P==0)
     {printf("1");
      return 0;
     }
    if(nr==P)
      printf("%d\n",i-5);
     else printf("-1");
    return 0;
}