#include <bits/stdc++.h> using namespace std; long long cf[100000],n,m,a[100000],x,y,z,ans; int main(){ cin>>n>>m; cin>>a[1]; for(long long i=2;i<=m;i++){ cin>>a[i]; if(a[i]>a[i-1]){ cf[a[i-1]]++; cf[a[i]]--; } else { cf[a[i-1]]--; cf[a[i]]++; } } for(long long i=1;i<n;i++){ a[i]=a[i-1]+cf[i]; cin>>x>>y>>z; ans+=min(a[i]x,z+ya[i]); } cout<<ans; return 0; }