#include<stdio.h> #include<stdlib.h> #include<string.h> #include<math.h> #define N 256 int comp(const void*a, const void*b) { return *((int *)a) - *((int *)b); } int find_kth_num(int nums[N], int length, int k) { int counts[1001]; int sum = 0; int i; memset(counts, 0, 1001 * sizeof(int)); qsort(nums, length, sizeof(int), comp); for (i = 0; i < length; i++) { sum += (counts[nums[i]] == 0); counts[nums[i]] = 1; if (sum == k) { return nums[i]; } } return -1; } int main() { int n = 0; int i; int nums[N]; scanf("%d", &n); for (i = 0; i < n; i++) { scanf("%d", nums + i); } printf("%d", find_kth_num(nums, n, 3)); return 0; }