#include<stdio.h>
int p,n;
void citire(){
   freopen("fact.in","r",stdin);
   scanf("%d",&p);
}
int nrzero(long n){
  int k=0;
  for(int i=5;i<=n;i*=5)
    k+=n/i;
  return k;
}
int pow5(int k){
    int nr=1;
    while(k!=0){
      nr*=5;
      k--;
   }
}               
int rezolvare(){
     int k=0,put=0;
     if(p==0)
       return 1;
     if(p<5)
       return p*5;
     int aux=p;
     while(aux>=5){
         aux/=5;
         put++;
     }             
     for(int i=pow5(put);i<=pow5(put)*25;i++)
         if(nrzero(i)==p)
             return i;
     return -1;            
      
}
void afisare(){
     freopen("fact.out","w",stdout);
     printf("%d",rezolvare());
     fclose(stdout);
}
int main(){
    citire();
    afisare();
    return 0;
}