func_code_string: #include <bits/stdc++.h>   using namespace std;   const int NN = 100 * 1000 + 5;   map<pair<pair<int, long long>, int>, long long> dp;   vector<int> adj[NN];   vector<long long> x;   long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }   const int mod = (int)1e9 + 7;   int rec(int node, int parent, long long g, int state) {     pair<pair<int, long long>, int> p = make_pair(make_pair(node, g), state);     if (dp.find(p) != dp.end()) return dp[p];     long long& res = dp[p];     res = gcd(g, x[node]);     res %= mod;     long long new_g = gcd(g, x[node]);     for (int child : adj[node]) {       if (child == parent) continue;       if (state == 0) {         res += rec(child, node, g, 0);         res %= mod;       }       res += rec(child, node, new_g, 1);       res %= mod;     }     return res;   }   int main() {     int n;     scanf( %d , &n);     x.resize(n);     for (int i = 0; i < n; i++) {       scanf( %lld , &x[i]);     }     for (int i = 0; i < n - 1; i++) {       int a, b;       scanf( %d%d , &a, &b);       a--;       b--;       adj[a].push_back(b);       adj[b].push_back(a);     }     long long ans = rec(0, -1, 0, 0);     cout << ans << endl;   }   