#include <cstdio>

using namespace std;

int zero(int x){
    //s= numarul de zerouri in care se termina x!
    int s=0,numitor=5;
    while(x/numitor>0){
        s=s+x/numitor;
        numitor=numitor*5;
    }
    return s;
}

int main(){
    freopen("fact.in","r",stdin);
    freopen("fact.out","w",stdout);
    int n;
    scanf("%d",&n);
    if(n==0){
        printf("1");
        return 0;
    }
    for(int i=5;i<=10000000;i=i+5){
        if(zero(i)==n){
            printf("%d",i);
            return 0;
        }
        if(zero(i)>n){
            printf("-1");
            return 0;
        }
    }
    return 0;
}