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#include<bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
typedef long long ll;
ll gcd(ll x,ll y){
	if(y==0) return x;
	return gcd(y,x%y);
}
int main()
{
	int n;
	ll a=0,b=0,x=0,y=0,A=0,B=0,g=0;
	scanf("%d",&n);//3
	if(n==1||n==0) return 0;
	for(int i=1;i<=n;i++){
		scanf("%d/%d",&a,&b);//1,1
		if(i==1){
		x=a;//1
		y=b;//1
		continue;
		}		
		A=b*x+a*y;//
		B=b*y;
		g=gcd(A,B);
		if(g!=1){
		A/=g;
		B/=g;			
		}

		x=A;
		y=B;
	}
	
	if(B==1){
	cout<<A;
	return 0;
	}
	cout<<A<<"/"<<B<<endl; 
	


 	return 0;
}

帮忙看看哪里错了