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

int main() {
    int P;

    FILE *in = fopen("fact.in", "rt");
    fscanf(in, "%d", &P);
    fclose(in);

    if (P == 0) {
        P = 1;            
    } else {
        if (P < 5) {
            P *= 5;
        } else if(P == 5) {
            P = -1;
        } else {
            P *= 5;
            P -= 5;
        }
    }

    FILE *out = fopen("fact.out", "wt");
    fprintf(out, "%d", P);
    fclose(in);
    return 0;
}