ccf202012-1期末预测之安全指数

 

 

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
using namespace std;
int w[100005],score[100005];
int main()
{
	int n;
	int y,result;
	while(cin>>n)
	{result=0;
		for(int i=0;i<n;i++)
		{
			cin>>w[i]>>score[i];
			result+=w[i]*score[i];
		}
		if(result<0)cout<<0;
		else
		cout<<result;
		cout<<endl;
	}
	return 0;
}