#include <stdio.h>

long long int P,p,nr,ind;

int main(){
	
	freopen("fact.in","r",stdin);  
	freopen("fact.out","w",stdout);

    //fin >> P;
    scanf("%llu\n", &P);

    while(p<P){
        nr+=5;
        ind=nr;
        while (ind%5==0){
            ind=ind/5;
            p++;
        }
    }

    if (p>P) nr=-1;
    if (P==0) nr=1;

    printf("%llu", nr);

}