I - Misha and Changing Handles CodeForces - 501B

#include<iostream>
#include<set>
#include<string>
#include<map>
#include<sstream>
#include<algorithm>
using namespace std;
string jiu[1010];
string xin[1010];
int main()
{
int n;
while(cin>>n)
{
int cishu=0,z=0,lala;
while(n--)
{
string str1,str2;
cin>>str1>>str2;
int jiaohuan=0;
for(int i=0;i<cishu;i++)
{
if(xin[i]==str1)
{
xin[i]=str2;
jiaohuan=1;
break;
}
}
if(jiaohuan==0)
{
jiu[cishu]=str1;
xin[cishu]=str2;
cishu++;
}
}
cout<<cishu<<endl;
for(int i=0;i<cishu;i++)
{
cout<<jiu[i]<<" "<<xin[i]<<endl;
}
}
}