Duff and Meat - CF 588A

#include<iostream>
#include<string.h>
#include<stdio.h>
#include<algorithm>
#include<math.h>
using namespace std;

const int MAXN = 17;
const int oo = 1e9+7;

int main()
{
    int N;

    while(scanf("%d", &N) != EOF)
    {
        int ai, pi, ans=0, MinP=oo;

        while(N--)
        {
            scanf("%d%d", &ai, &pi);
            MinP = min(MinP, pi);
            ans += ai * MinP;
        }

        printf("%d\n", ans);
    }

    return 0;
}