I just can't find where's mistake - i always get WA at test #1:

#include<iostream>
#include<string>
#include<vector>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<set>
#define REP(i,n) for(int i=0;i<n;i++)
#define REPD(i,n) for(int i=n;i>-1;i--)
#define FOR(i,j,k) for(int i=j;i<k;i++)
#define FORD(i,j,k) for(int i=j;i>k;i--)
#define PB push_back

using namespace std;


int main()
{
    int n;
    cin>>n;

    int X=0,Y=0,Z=0;

    REP(i,n)
    {
            char a;int p;
            cin>>a;cin>>p;
            if(a=='X') X+=p;
             else if(a=='Y') Y+=p;
              else Z+=p;
    }
    X+=Y;Z+=Y;

    if(X==0&&Z==0) cout<<"0"<<endl;

    else if(X==0) { cout<<"1"<<endl;cout<<"Z: "<<(-1)*Z<<endl;}
    else if(Z==0){ cout<<"1"<<endl; cout<<"X: "<<(-1)*X<<endl;}
    else if(abs(X)==abs(Z)) { cout<<"1"<<endl;cout<<"Y: "<<(-1)*X<<endl;}
  else  if(X>0&&Z>0)
    {
        int minimum=X+Z;
    int a=min(X,Z);

            if(X<Z)
            { cout<<"2"<<endl;
                     cout<<"Y: "<<(-1)*a<<endl;
                     cout<<"Z: "<<(-1)*(Z-a)<<endl;
            }
            else
             { cout<<"2"<<endl;
                     cout<<"X: "<<(-1)*(X-a)<<endl;
                     cout<<"Y: "<<(-1)*a<<endl;
            }
    }
    else if(X<0&&Z<0)
    {
          int minimum=X+Z;
          int a=abs(max(X,Z));
                if(X<Z)
            {
                       cout<<"2"<<endl;
                       cout<<"X: "<<(-1)*(X+a)<<endl;
                     cout<<"Y: "<<a<<endl;
            }
            else
             { cout<<"2"<<endl;
                     cout<<"Y: "<<a<<endl;
                     cout<<"Z: "<<(-1)*(Z+a)<<endl;
            }

    }
    else
    { cout<<"2"<<endl;
             cout<<"X: "<<(-1)*X<<endl;
                     cout<<"Z: "<<(-1)*Z<<endl;
    }

    int p;cin>>p;

}