#define HAVE_STRUCT_TIMESPEC

 #include<bits/stdc++.h>

 using namespace std;

 int a[],b[];

 int main(){

     ios::sync_with_stdio(false);

     cin.tie(NULL);

     cout.tie(NULL);

     int n;

     cin>>n;

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

         cin>>a[i];

         cin.ignore();

         cin>>b[i];

         int t=max(,__gcd(a[i],b[i]));

         a[i]/=t;

         b[i]/=t;

     }

     int ans=;

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

         int tamp=b[i-]*b[i];

         int sum=a[i]*b[i-]+a[i-]*b[i];

         int t=__gcd(tamp,sum);

         tamp/=t;

         sum/=t;

         ans+=sum/tamp;

         sum%=tamp;

         a[i]=sum;

         b[i]=tamp;

     }

     if(ans&&a[n])

         cout<<ans<<" "<<a[n]<<"/"<<b[n];

     else if(ans)

         cout<<ans;

     else if(a[n])

         cout<<a[n]<<"/"<<b[n];

     else

         cout<<;

     return ;

 }