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

int main(int argc, char* argv[])
{

    srand(time(0));
    if(argc!=2)
    {
        printf("Hiba! Nincs megadva argumentum! A program leall!");
        return -1;
    }

    int N = atoi(argv[1]);
    int csucs[8][3] = {{1,3,5},{0,2,6},{1,3,7},{0,2,4},{3,5,7},{0,4,6},{1,5,7},{2,4,6}};
    int lepesek = 0;
    int i, poz = 0;
    for(i=0; i<N; i++)
    {
        poz = 0;
        while(poz!=7)
        {
            int r = rand()%3;
            poz = csucs[poz][r];
            lepesek++;
        }
    }
    printf("%.5f",lepesek*1.0/N);

return 0;
}