#include <stdio.h>  
 int main(void)   
 {  
     freopen("fact.in", "r", stdin);  
     long P;  
     scanf("%ld", &P);  
     fclose(stdin);  
     int c=0, i, j;  
     for(i=2;c<P;i++) {j=i;  
                       while (j%5==0) {c++;j=j/5;}  
                      }  
     freopen("fact.out", "w", stdout);  
     if (c==P) printf("%d", i-1);   
     else printf("%d", -1);  
     fclose(stdout);  
     return 0;  
 }