P1534，求解

#include<bits/stdc++.h>
using namespace std; 
int main(){
   int n,s,d;
   cin>>n;
   for(int i=1;i<=n;i++){
   	int a,b;
       cin>>a>>b;
       s=s+a+b-8;  
       d+=s;
   }
   cout<<d;  
   return 0;             
}