#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ int a[1001],b[1001],s=0,n,i; cin>>n; for (i=1;i<=n;i++) cin>>a[i]; for (i=1;i<=n;i++) cin>>b[i]; for (i=1;i<=n;i++) s=s+a[i]*b[i]; cout<<s; return 0; }