#include<stdio.h>
int main() {
    int n;
    scanf("%d",&n);
    if(n < 0 || n > 10) {
        printf("Invalid input");
    return 0;
    }
    int rolls[20],seen[21] = {0};
    for(int i = 0;i < n;i++) {
        scanf("%d",&rolls[i]);
        if(rolls[i]) < -10 || rolls[i] > 10 {
            printf("Invalid input");
            return 0;
        }
    }
    for(int i = 0;i < n; i++) {
        if(!seen[rolls[i] + 10]) {
            printf("%d\n",rolls[i]);
            seen[rolls[i] + 10] = 1;
        }
    }
    return 0;
}