func_code_string: #include <bits/stdc++.h>   using namespace std;   map<pair<int, int>, bool> mp;   pair<int, int> ara[400005];   int main() {     int n, m, x;     scanf( %d %d , &n, &m);     for (int i = 1; i <= m; i++) {       scanf( %d %d , &ara[i].first, &ara[i].second);       ara[i].first %= n, ara[i].second %= n;       if (ara[i].first > ara[i].second) swap(ara[i].first, ara[i].second);       ara[i + m] = ara[i], mp[ara[i]] = 1;     }     bool f = 0;     for (int i = 1; i * i <= n && !f; i++)       if (!(n % i)) {         x = i;         bool f2 = 1;         for (int j = 1; j <= m && f2; j++) {           int a = (ara[j].first + x) % n;           int b = (ara[j].second + x) % n;           if (a > b) swap(a, b);           f2 = mp[{a, b}];         }         f = f2;         x = (n / i);         if (x == n || f) continue;         f2 = 1;         for (int j = 1; j <= m && f2; j++) {           int a = (ara[j].first + x) % n;           int b = (ara[j].second + x) % n;           if (a > b) swap(a, b);           f2 = mp[{a, b}];         }         f = f2;       }     if (f)       printf( Yes n );     else       printf( No n );     return 0;   }   