import
java.util.*;
class
GFG
{
static
ArrayList<Integer> findnum(String s1)
{
ArrayList<Integer> v =
new
ArrayList<Integer>();
int
a =
0
, b =
0
;
int
sa =
0
, sb =
0
, i =
0
;
if
(s1.charAt(
0
) ==
'-'
) {
sa =
1
;
i =
1
;
}
while
(Character.isDigit(s1.charAt(i))) {
a = a *
10
+ (s1.charAt(i) -
'0'
);
i++;
}
if
(s1.charAt(i) ==
'+'
) {
sb =
0
;
i +=
1
;
}
if
(s1.charAt(i) ==
'-'
) {
sb =
1
;
i +=
1
;
}
while
(i < s1.length() && Character.isDigit(s1.charAt(i))) {
b = b *
10
+ (s1.charAt(i) -
'0'
);
i++;
}
if
(sa !=
0
)
a *= -
1
;
if
(sb !=
0
)
b *= -
1
;
v.add(a);
v.add(b);
return
v;
}
static
String complexNumberMultiply(ArrayList<String> v)
{
while
(v.size() !=
1
)
{
ArrayList<Integer> v1 = findnum(v.get(
0
));
ArrayList<Integer> v2 = findnum(v.get(
1
));
v.remove(
0
);
v.remove(
0
);
int
r = (v1.get(
0
) * v2.get(
0
) - v1.get(
1
) * v2.get(
1
));
int
img = v1.get(
0
) * v2.get(
1
) + v1.get(
1
) * v2.get(
0
);
String res =
""
;
res += String.valueOf(r);
res +=
'+'
;
res += String.valueOf(img) +
'i'
;
v.add(
0
, res);
}
return
v.get(
0
);
}
public
static
void
main(String[] args)
{
int
n =
3
;
ArrayList<String> v =
new
ArrayList<String>();
v.add(
"3+1i"
);
v.add(
"2+1i"
);
v.add(
"-5+-7i"
);
System.out.println(complexNumberMultiply(v));
}
}