#include <stdio.h>
#include <stdlib.h>
 
int main() {
    int n;
    scanf("%d", &n);
 
    int *A = (int *)malloc((n + 1) * sizeof(int));
    int *prefix = (int *)malloc((n + 1) * sizeof(int));
 
    // Baca array (1-indexed)
    prefix[0] = 0;
    for (int i = 1; i <= n; i++) {
        scanf("%d", &A[i]);
        prefix[i] = prefix[i - 1] + A[i];
    }
 
    // Jawab query hingga sentinel -9
    int L;
    while (scanf("%d", &L) == 1 && L != -9) {
        int R;
        scanf("%d", &R);
        printf("%d\n", prefix[R] - prefix[L - 1]);
    }
 
    free(A);
    free(prefix);
    return 0;
}

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NQoxMCAyNSAzMSA0MiA1NwoxIDQKMSA1CjIgMwo0IDUKLTk=

5
10 25 31 42 57
1 4
1 5
2 3
4 5
-9