模拟

#include<iostream>
using namespace std;
int main(){
    int n;
    cin>>n;
    int k=0;
    int sum=0;
    for(int i=1;i<=n;i++){
        int x,y;
        cin>>x>>y;
        k+=(x+y);
        k-=8;
        sum+=k;
    }
    cout<<sum;
}