#include <stdio.h>

int main() {
    int n, i;
    float arr[1000];
    float *p;

    // Read the size of the array
    scanf("%d", &n);

    // Check for invalid input
    if (n <= 0 || n > 1000) {
        printf("Invalid Input\n");
        return 0;
    }

    // Read the array elements
    for (i = 0; i < n; i++)
        scanf("%f", &arr[i]);

    // Double each element using pointer arithmetic
    p = arr;
    for (float i = 0; i < n; i++) {
        (p + i) = 2 * ((p + i));
    }

    // Output the modified array
    for (i = 0; i < n; i++)
        printf("%.2f ", arr[i]);
    printf("\n");

    return 0;
}