#include<stdio.h>
#include<stdlib.h>

int intcmp (const void * a, const void * b)
    int _a = *(int*)a;
    int _b = *(int*)b;
    return (_a - _b);
}
/*
int my_compare (const void * a, const void * b)
{
    int _a = *(int*)a;
    int _b = *(int*)b;
    return ( _a - _b );
}
*/

int main(void){

    int n, i=0, j=1, t[100000];
    int last=t[0];
    scanf("%d", &n);
    for(i=0; i<n; i++){
        scanf("%d", &t[i]);
    }
    qsort(t, n, sizeof(t[0]), intcmp);
    for(j=1; j<n; j++){
        if(t[j]==last){
            printf("%d\n", t[j]);
            while(last==t[j]) j++;
        }
        else{
            last=t[j];
            j++;
        }
    }

    system("pause");
    return 0;
}