#include <bits/stdc++.h>   using namespace std;   const int maxn = 200025;   int n, m, i, j, t, k, s, mod, a[maxn], fat[maxn];   bool flg, vis[maxn << 1];   inline int Pow(int x, int y, int mo) {     int ret = 1;     while (y) {       if (y & 1) ret = 1ll * ret * x % mo;       x = 1ll * x * x % mo;       y >>= 1;     }     return ret;   }   int father(int x) { return x == fat[x] ? x : fat[x] = father(fat[x]); }   void solve(int delt) {     for (i = 1; i <= n; ++i) fat[i] = i;     for (i = 1; i <= n; ++i) {       k = (a[i] - delt + mod) % mod;       t = lower_bound(a + 1, a + n + 1, k) - a;       if (a[t] == k) fat[father(t)] = father(i);     }     t = 0;     for (i = 1; i <= n; ++i) {       if (fat[i] == i)         t++;       else         fat[i] = i;     }     delt = delt * 1ll * Pow(t, mod - 2, mod) % mod;     for (i = 1; i <= n; ++i) {       k = (a[i] - delt + mod) % mod;       t = lower_bound(a + 1, a + n + 1, k) - a;       if (a[t] == k) fat[father(t)] = father(i);     }     for (i = 2; i <= n; ++i)       if (father(i) ^ father(1)) break;     if (i > n) {       for (i = 1; i <= n; ++i) {         k = (a[i] - delt + mod) % mod;         t = lower_bound(a + 1, a + n + 1, k) - a;         if (a[t] != k) break;       }       if (i > n) {         if (flg)           printf( %d %d n , a[1], delt);         else           t = (1ll * n * delt + a[1]) % mod, printf( %d %d n , t, delt);       } else {         if (flg)           printf( %d %d n , a[i], delt);         else           t = (1ll * n * delt + a[i]) % mod, printf( %d %d n , t, delt);       }       exit(0);     }   }   int main() {     scanf( %d%d , &mod, &n);     for (i = 1; i <= n; ++i) scanf( %d , &a[i]);     a[n + 1] = mod + 114514;     if (n == 1 || n == mod) {       printf( %d %d n , a[1], 1);       return 0;     }     if (n == 2) {       printf( %d %d n , a[1], (a[2] - a[1] + mod) % mod);       return 0;     }     sort(a + 1, a + n + 1);     flg = 1;     if (2 * n > mod) {       flg = 0;       for (i = 1; i <= n; ++i) vis[a[i]] = 1;       n = 0;       for (i = 0; i < mod; ++i)         if (!vis[i]) a[++n] = i;       a[n + 1] = mod + 114514;       if (n == 1) {         printf( %d %d n , (a[1] + 1) % mod, 1);         return 0;       }     }     solve(a[2] - a[1]);     solve((a[1] - a[2] + mod) % mod);     puts( -1 );     return 0;   }   