func_code_string: #include <bits/stdc++.h>   using namespace std;   int g[100010];   int main(void) {     int A, T, N, M;     scanf( %d , &N);     for (int i = (int)(3); i <= (int)(N); i++) {       set<int> st;       A = 2000000000;       for (int j = (int)(2); j <= (int)(N); j++) {         int k = i - j * (j + 1) / 2;         if (k < 0) break;         if (k % j != 0) continue;         int l = 1 + k / j, r = j + k / j, nim = 0;         while (l <= r) {           nim = nim ^ g[l++];         }         st.insert(nim);         if (nim == 0) A = min(A, j);       }       int res = 0;       while (st.find(res) != st.end()) res++;       g[i] = res;     }     if (g[N])       printf( %d n , A);     else       printf( -1 n );     return 0;   }   