func_code_string: #include <bits/stdc++.h>   using namespace std;   const int mod = 1000000007;   int n;   vector<pair<int, long long> > fa[100], fb[100];   long long powmod(long long a, long long k) {     long long ret = 1;     while (k) {       if (k & 1) {         ret = ret * a % mod;       }       a = a * a % mod;       k >>= 1;     }     return ret;   }   long long exgcd(long long a, long long b, long long& x, long long& y) {     if (!b) {       x = 1;       y = 0;       return a;     }     long long d = exgcd(b, a % b, y, x);     y -= x * (a / b);     return d;   }   long long find(const vector<pair<int, long long> >& f, int p) {     int pos = lower_bound(f.begin(), f.end(), make_pair(p, -1ll)) - f.begin();     if (pos != f.size() && f[pos].first == p) {       return f[pos].second;     }     return 0;   }   vector<pair<int, long long> > factor(int x) {     vector<pair<int, long long> > ret;     for (int i = 2; i * i <= x; ++i) {       long long cnt = 0;       while (x % i == 0) {         cnt++;         x /= i;       }       if (cnt) {         ret.push_back(make_pair(i, cnt));       }     }     if (x > 1) {       ret.push_back(make_pair(x, 1));     }     return ret;   }   void addfirst(vector<int>& s, const vector<pair<int, long long> >& t) {     for (int i = 0; i < t.size(); ++i) {       s.push_back(t[i].first);     }   }   bool solve() {     while (n > 1) {       int cnt = 0;       for (int i = 0; i < n - 1; ++i) {         vector<int> v;         addfirst(v, fa[i]);         addfirst(v, fb[i]);         addfirst(v, fa[i + 1]);         addfirst(v, fb[i + 1]);         sort(v.begin(), v.end());         v.erase(unique(v.begin(), v.end()), v.end());         long long px = -1, py, sx, sy;         for (int j = 0; j < v.size(); ++j) {           long long a1 = find(fa[i], v[j]), a2 = find(fa[i + 1], v[j]);           long long b1 = find(fb[i], v[j]), b2 = find(fb[i + 1], v[j]);           long long x, y, dx, dy;           long long d = exgcd(b1, -b2, x, y);           if (b1 == 0 && b2 == 0) {             if (a1 != a2) {               return false;             }             continue;           } else if (b1 == 0 && a1 >= a2 && (a1 - a2) % b2 == 0) {             x = 0;             y = (a1 - a2) / b2;             dx = 1;             dy = 0;           } else if (b2 == 0 && a2 >= a1 && (a2 - a1) % b1 == 0) {             x = (a2 - a1) / b1;             y = 0;             dx = 0;             dy = 1;           } else if (d == 0 || (a2 - a1) % d != 0) {             return false;           } else {             x *= (a2 - a1) / d;             y *= (a2 - a1) / d;             dx = b2 / abs(d);             dy = b1 / abs(d);             if (x > 0 && dx > 0) {               long long t = (x - 1) / dx + 1;               x -= t * dx;               y -= t * dy;             }             if (y > 0 && dy > 0) {               long long t = (y - 1) / dy + 1;               x -= t * dx;               y -= t * dy;             }             if (x < 0) {               if (dx == 0) {                 return false;               }               long long t = (-x - 1) / dx + 1;               x += t * dx;               y += t * dy;             }             if (y < 0) {               if (dy == 0) {                 return false;               }               long long t = (-y - 1) / dy + 1;               x += t * dx;               y += t * dy;             }           }           if (px == -1) {             px = x;             py = y;             sx = dx;             sy = dy;           } else {             if (sx != 0 || sy != 0) {               if (sx != dx || sy != dy) {                 long long k1 =                     ((x - px) * dy - (y - py) * dx) / (sx * dy - sy * dx);                 long long nx = px + sx * k1, ny = py + sy * k1;                 if (nx < x || ny < y || (nx - x) * dy - dx * (ny - y) != 0) {                   return false;                 }                 px = nx;                 py = ny;                 sx = sy = 0;               } else if ((px - x) * dy - dx * (py - y) != 0) {                 return false;               }             } else if (px < x || py < y || (px - x) * dy - dx * (py - y) != 0) {               return false;             }           }         }         if (px != -1) {           vector<pair<int, long long> > nfa, nfb;           for (int j = 0; j < v.size(); ++j) {             long long a1 = find(fa[i], v[j]), b1 = find(fb[i], v[j]);             if (b1 * px + a1) {               nfa.push_back(make_pair(v[j], b1 * px + a1));             }             if (b1 * sx) {               nfb.push_back(make_pair(v[j], b1 * sx));             }           }           fa[cnt] = nfa;           fb[cnt++] = nfb;         }       }       n = cnt;     }     return true;   }   int main() {     scanf( %d , &n);     for (int i = 0; i < n; ++i) {       int a, b;       scanf( %d %d , &a, &b);       fa[i] = factor(a);       fb[i] = factor(b);     }     if (solve()) {       long long ans = 1;       for (int i = 0; i < fa[0].size(); ++i) {         ans = ans * powmod(fa[0][i].first, fa[0][i].second) % mod;       }       printf( %I64d n , ans);     } else {       printf( -1 n );     }     return 0;   }   