func_code_string: #include <bits/stdc++.h>   using namespace std;   void dbg_out() { cerr <<   b b] n ; }   template <typename Head, typename... Tail>   void dbg_out(Head H, Tail... T) {     cerr << H <<  ,  ;     dbg_out(T...);   }   const int mod = 1e9 + 7;   long long power(long long a, long long b) {     long long res = 1;     while (b) {       if (b & 1) res = res * a % mod;       a = a * a % mod;       b >>= 1;     }     return res;   }   long long modMul(long long a, long long b) { return a * b % mod; }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(nullptr);     int n, k;     cin >> n >> k;     vector<int> A(n / k), B(n / k);     for (int &i : A) cin >> i;     for (int &i : B) cin >> i;     long long ans = 1;     long long tens = power(10, k - 1);     for (int i = 0; i < n / k; ++i) {       long long tot = (tens * 10 - 1) / A[i] + 1;       long long lo = B[i] * tens;       long long hi = B[i] * tens + tens - 1;       long long invalid = hi / A[i] - lo / A[i] + (lo % A[i] == 0);       tot -= invalid;       ans = modMul(ans, tot);     }     cout << ans;     return 0;   }   