BRIN.cpp

#include <bits/stdc++.h>
#define ll long long
#define get(a) scanf("%lld", &a);
#define rep(n) for( ll i = 1; i <= n; i++ )
#define repVector(v)  for( typeof(v.begin()) it = v.begin(); it != v.end(); it++ )
#define repSet(s) for( typeof(s.begin()) it = s.begin(); it != s.end(); it++ )
#define all(c) c.begin(), c.end()
#define pb push_back
#define absol(a) ( ( a >= 0 ) ? a : -a )
#define FOR(i,a,b) for( ll i = a; i <= b; i++ )
#define ROF(i,a,b) for( ll i = a; i >= b; i-- )
#define debug(x) cout << "[DEBUG] " << #x << " = " << x << endl
#define matrix vector< vector<ll> >
#define F first
#define S second
#define mp make_pair
#define L 2*r
#define R 2*r+1
#define INPFILE freopen("input.in","r",stdin)
using namespace std;

int main() {
	ll t; get(t);
	while(t--) {
		ll n; get(n);
		char str[1005][1005];
		ll y[1005] = {0}, x = 0;
		
		FOR(i,1,n)
		 scanf("%s", str[i]+1);
		ll ans = 0;
		
		FOR(i,1,n) {
			x = 0;
		 ROF(j,n,1) {
		 	ll id = str[i][j] - '0';
		 	
		 	if( ( y[j]^id^x ) )
		 	  { ans++; x ^= 1; y[j] ^= 1;  }
		  }
		}
		 
		 printf("%lld\n", ans);
	}

}