#include <stdio.h>

int f1(int *a, int begin, int end)      //折半遞迴求和
{
    int mid;
    if(begin + 1 == end)    // [begin, ..., mid) + [mid, ..., end)
        return a[begin];

    mid = (begin + end) / 2;
    return f1(a, begin, mid) + f1(a, mid, end);
}

int f2(int *a, int begin, int lenth)    //a[begin] + SUM(a[begin + 1], ...... a[結束])
{
    if(begin == lenth)
        return 0;
    else
        return a[begin] + f2(a, begin + 1, lenth);
}

int f3(int *a, int end)                 //SUM(a[0], ......, a[end - 1]) + a[end]
{
    if(end == -1)
        return 0;
    else
        return f3(a, end - 1) + a[end];
}

int main()
{
    int a[100] = {0};
    int n, i;
    scanf("%d", &n);
    for(i=0; i<n; i++)
        scanf("%d", a+i);
    printf("%d\n", f1(a, 0, n));    //第一種結果
    printf("%d\n", f2(a, 0, n));    //第二種結果
    printf("%d\n", f3(a, n));        //第三種結果

    return 0;
}