string(1) "a"
string(1) "b"
string(1) "c"
int(0)
string(1) "a"
int(1)
string(1) "b"
int(2)
string(1) "c"
int(2)
string(1) "c"

string(1) "d"
string(1) "e"
string(1) "f"
int(0)
string(1) "d"
int(1)
string(1) "e"
int(2)
string(1) "f"
int(2)
string(1) "f"

string(1) "a"
string(1) "a"