题解

#include<bits/stdc++.h>
using namespace std;
long long f(long long a, long long b){
    if(a % b == 0) return b;
    return f(b, a % b);
}
int main(){
	long long fz = 0, fm = 1;
    int n, p, q;
    cin >> n;
    while(n--){
        scanf("%d/%d", &p, &q);
        fz = fz * q + fm * p;
        fm = fm * q;
        long long t  = f(fz, fm);
        fz /= t, fm /= t;
    }
    if(fm == 1) cout << fz;
    else cout << fz << "/" << fm;
	return 0;
}