#include<bits/stdc++.h>

#define LL long long

#define ll long long

#define fi first

#define se second

#define mk make_pair

#define PII pair<int, int>

#define y1 skldjfskldjg

#define y2 skldfjsklejg

using namespace std;

const int N = 2e5 + ;

const int M = 1e7 + ;

const int inf = 0x3f3f3f3f;

const LL INF = 0x3f3f3f3f3f3f3f3f;

const int mod = 1e9 +;

struct node {

    LL x, y;

    node(LL x = , LL y = ) {

        this->x = x;

        this->y = y;

    }

    bool operator < (const node &rhs) const {

        if(x == rhs.x) return y < rhs.y;

        return x < rhs.x;

    }

} a[N];

int n, tot, head, rear, stk[N];

LL dp[N];

bool check1(int id1, int id2, LL c) {

    return dp[id2] - dp[id1] <= c * (a[id1 + ].y - a[id2 + ].y);

}

bool check2(int id1, int id2, int id3, int id4) {

    return (dp[id4] - dp[id3]) * (a[id1 + ].y - a[id2 + ].y) <= (dp[id2] - dp[id1]) * (a[id3 + ].y - a[id4 + ].y);

}

int main() {

    scanf("%d", &n);

    for(int i = ; i <= n; i++) {

        scanf("%lld%lld", &a[i].x, &a[i].y);

    }

    sort(a + , a +  + n);

    tot = ;

    for(int i = ; i <= n; i++) {

        while(tot && a[i].y >= a[tot].y) tot--;

        a[++tot] = a[i];

    }

    n = tot;

    dp[] = ;

    stk[++rear] = ;

    for(int i = ; i <= n; i++) {

        while(rear > head && check1(stk[head], stk[head + ], a[i].x)) head++;

        int id = stk[head];

        dp[i] = dp[id] + a[id + ].y * a[i].x;

        while(rear > head && check2(stk[rear - ], stk[rear], stk[rear], i)) rear--;

        stk[++rear] = i;

    }

    printf("%lld\n", dp[n]);

    return ;

}

/*

*/