/* -*- coding: utf-8 -*- * * 754.cc: No.754 畳み込みの和 - yukicoder */ #include<cstdio> #include<cstdlib> #include<cstring> #include<cmath> #include<iostream> #include<string> #include<vector> #include<map> #include<set> #include<stack> #include<list> #include<queue> #include<deque> #include<algorithm> #include<numeric> #include<utility> #include<complex> #include<functional> using namespace std; /* constant */ const int MAX_N = 100000; const int MOD = 1000000007; /* typedef */ typedef long long ll; /* global variables */ int as[MAX_N + 1], bs[MAX_N + 1], asums[MAX_N + 2]; /* subroutines */ /* main */ int main() { int n; scanf("%d", &n); for (int i = 0; i <= n; i++) scanf("%d", as + i), asums[i + 1] = (asums[i] + as[i]) % MOD; for (int i = 0; i <= n; i++) scanf("%d", bs + i); int c = 0; for (int i = 0; i <= n; i++) c = (c + (ll)asums[i + 1] * bs[n - i] % MOD) % MOD; printf("%d\n", c); return 0; }