func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MaxN = 100000 + 5;   int N;   map<int, int> Numbers;   int main(void) {     scanf( %d , &N);     if (N % 2) {       printf( NO n );       return 0;     }     for (int i = 0; i < N; i++) {       int Number;       scanf( %d , &Number);       Numbers[Number]++;     }     while (!Numbers.empty()) {       while (!Numbers.begin()->second) Numbers.erase(Numbers.begin());       int Number = Numbers.begin()->first;       if (N == 2) {         if (Numbers[Number + 1] == 1)           printf( YES n );         else           printf( NO n );         return 0;       }       if (Numbers[Number + 1] < 2) {         printf( NO n );         return 0;       }       Numbers[Number]--;       Numbers[Number + 1]--;       N -= 2;     }     return 0;   }   