#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main()
{
    int fact=1, c=0, prod=1, z = 1;
    int p;
    FILE *f = fopen("fact.in", "r");
    FILE *g = fopen("fact.out", "w");

    fscanf(f, "%d", &p);

    for(int i = 1; i<=p;i++)
    {
        z*=10;
    }

    while(c==0)
    {
        prod = prod * ++fact;
        if(prod%z==0)
            c=1;
    }

    fprintf(g, "%d", fact);

    return 0;
}