#include <stdio.h>

int calc_five( int n )
{
    int c=0;
    while( n%5 ==0 )
    {
        c++;
        n/=5;
    }
    return c;
}

int calc_n( int p )
{
    int putere=0;
    int aux=1, i=1;
    if(p==0) return 1;
    while( putere<p )
    {
        aux=5*i;
        int c=calc_five(aux);
        //printf("ceva");
        i++;
        putere=putere+c;
    }
    return aux;
}

int main()
{
    int p;
    FILE *f = fopen("fact.in", "r");
    FILE *f2 = fopen("fact.out", "w");
    fscanf(f, "%d", &p);
    fprintf(f2, "%d", calc_n(p));
    printf("%d ", calc_n(p));
    return 0;
}