100Pts求调

#include<bits/stdc++.h>
#define int long long 
using namespace std;
int n,m[20],a[20];
int exgcd(int a,int b,int &x,int &y)
{
	if(b==0)
	{
		x=1;y=0;return a;
	}
	int r=exgcd(b,a%b,x,y);
	int tem=x;
	x=y;
	y=tem-a/b*y;
	return r; 
}
int zgsydl()
{
    int ans=0,x,y,M=1,mi;
    for (int i=0;i<n;++i) M*=m[i];
    for (int i=0;i<n;++i)
	{
        mi=M/m[i];
        exgcd(mi,m[i],x,y);
        ans=(ans+a[i]*mi%M*x%M)%M;
    }
    return (ans+M)%M;
}

signed main()
{
    cin>>n;
    for (int i=0;i<n;++i) cin>>m[i]>>a[i];
    cout<<zgsydl()<<endl;
    return 0;
}