func_code_string: #include <bits/stdc++.h>   using namespace std;   inline long long read() {     char ch = getchar();     long long res = 0, pd = 1;     while (ch <  0  || ch >  9 ) {       if (ch ==  - ) pd = -1;       ch = getchar();     }     while (ch >=  0  && ch <=  9 ) {       res = (res << 1) + (res << 3) + ch -  0 ;       ch = getchar();     }     return res * pd;   }   inline void write(long long x) {     if (x < 0) putchar( - ), x = -x;     if (x > 9) write(x / 10);     putchar(x % 10 |  0 );   }   inline void wlk(long long x) {     write(x);     putchar(32);   }   inline void wln(long long x) {     write(x);     putchar(10);   }   const long long maxn = 100003;   long long a[maxn];   signed main() {     long long n = read(), flag = 1;     for (long long i = 1; i <= n; ++i) a[i] = read();     for (long long i = 2; i <= n; ++i)       if (a[i] % a[1] != 0) flag = 0;     if (!flag) return puts( -1 ), 0;     wln(2 * n);     for (long long i = 1; i <= n; ++i) {       wlk(a[1]), wlk(a[i]);     }     return puts(  ), 0;   }   