#include <iostream>
int main() {
    int c = 1;
    uint64_t P, k = 0;
    FILE * fisier_out = fopen("fact.out", "w");
    FILE * fisier_in = fopen("fact.in", "r");
    fscanf(fisier_in, "%llu", &P);

    if((P+1) % 6 == 0){
        fprintf(fisier_out, "%d", -1);
        return 0;
    }
    while(1){
        k = 0;
       
        for(int i = c; i >= 1; i--){
            if(i % 5 == 0){
                k = k + 1;
            }
            if(i % 25 == 0){
                k = k + 1;
            }
        }
        if(k == P){
            fprintf(fisier_out, "%d", c);
            break;
        }
        c = c + 1;
    }
    fclose(fisier_in);
    fclose(fisier_out);
    return 0;
}