#include <stdio.h>
int main(){
    int n,a[1000000],i,j,c;
    scanf("%d",&n);
    for(i=0;i<n:i++)scanf("%d",&a[i]);
    for(i=0;i<n;i++){
        c=0;
        for(j=0;j<n;j++)if(a[i]==a[j])c++;
        if(c==1)printf("%d\n",a[i]);
    }
}