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

int main()
{
    int L;
    int i;
    clock_t t_start, t_end, t_total;
    int sum = 0;
    scanf("%d", &L);
    {
        int* p = (int*)malloc(L * sizeof(int));
        int* a = (int*)malloc(L * sizeof(int));
        for (i = 0; i < L; ++i)
            scanf("%d", &a[i]);
        for (i = 0; i < L; ++i)
            p[i] = i;
        t_start = clock();
        for (i = 0; i < L; ++i)
            sum += a[p[i]];
        t_end = clock();
        t_total = (double)(t_end - t_start) / CLOCKS_PER_SEC;
        printf("%lf", t_total);
    }
    return 0;
}