Snake Procession(codechef)

problem id:--https://www.codechef.com/SNCKQL17/problems/SNAKPROC

code:--


#include<iostream>
using namespace std;
int main()
{
int t;
cin>>t;
while(t--)
{
int l;
cin>>l;
string str;
cin>>str;
int i=0,flag=1;
string ans[]={"Invalid","Valid"};
while(str[i]!='\0')
{
if(str[i]!='.')
{
if(str[i]=='H' && flag==1)
flag=2;
else if(str[i]=='T' && flag==2)
flag=1;
else
{
flag=2;
break;
}
}
++i;
}
cout<<ans[(flag&1)]<<'\n';
}
return 0;
}