80分， 不明白哪有问题

#include <bits/stdc++.h>

using namespace std;

const int N = 2e4 + 10;
struct people{
	int a, b;
}ps[N];
int n;
int Len = 4005;
int s[4005], t[4005], ans[4005];

inline bool cmp(people x, people y){
	return max(x.a * x.b, y.b) < max(y.a * y.b, x.b);
}

inline void cheng(int d){
	for (int i = 1; i <= Len; i++) s[i] *= d;
	for (int i = 1; i <= Len; i++){
		s[i + 1] += s[i] / 10;
		s[i] %= 10;
	}
}

inline void chu(int d){
	memset(t, 0, sizeof(t));
	int r = 0;
	for (int i = Len; i >= 1; i--){
		r = r * 10 + s[i];
		t[i] = r / d;
		r %= d;
	}
}

inline bool f(){
	for (int i = Len; i >= 1; i--){
		if (t[i] > ans[i]) return true;
		if (t[i] < ans[i]) return false;
	}
	return false;
}

inline void cop(){
	for (int i = 1; i <= Len; i++) ans[i] = t[i];
}

inline void print(){
	while (ans[Len] == 0 && Len > 1) Len--;
	for (int i = Len; i >= 1; i--) cout << ans[i];
	cout << "\n";
}

int main(){
	cin >> n;
	for (int i = 0; i <= n; i++)
		cin >> ps[i].a >> ps[i].b;
	sort(ps + 1, ps + 1 + n, cmp);
	s[1] = 1;
	for (int i = 1; i <= n; i++){
		cheng(ps[i - 1].a);
		chu(ps[i].b);
		if (f()) cop();
	}
	print();
	return 0;
}