From 8f3070f32aaf2a5ab2e8b06ec3c036ffc620569e Mon Sep 17 00:00:00 2001
From: venkyvt7 <venkateshp.tripathi@gmail.com>
Date: Fri, 2 Oct 2020 21:27:08 +0530
Subject: [PATCH] added 1367B.

---
 Codeforces/1367B.cpp | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 Codeforces/1367B.cpp

diff --git a/Codeforces/1367B.cpp b/Codeforces/1367B.cpp
new file mode 100644
index 0000000..e907084
--- /dev/null
+++ b/Codeforces/1367B.cpp
@@ -0,0 +1,41 @@
+#include<bits/stdc++.h>
+
+using namespace std;
+
+int main()
+{
+	int t;
+	cin>>t;
+	while(t--)
+	{
+		int n,i,j,k;
+		int a[10000];
+		
+		cin>>n;
+		
+		int even=0,odd=0;
+		for(i=0;i<n;i++)
+		{
+			cin>>a[i];
+      
+			if(a[i]%2!=i%2)
+			{
+				if(a[i]%2==0)
+				even++;
+				
+				else
+				odd++;
+				
+				
+			}	
+		}
+		
+		if(even==odd)
+		cout<<even;
+		
+		else
+		cout<<-1;
+		
+	cout<<endl;
+	}
+}