diff --git a/zeta_python/11726.py b/zeta_python/11726.py
new file mode 100644
index 0000000..e69de29
diff --git a/zeta_python/1485.py b/zeta_python/1485.py
new file mode 100644
index 0000000..228c28b
--- /dev/null
+++ b/zeta_python/1485.py
@@ -0,0 +1,33 @@
+N = int(input())
+
+
+def check90(p1, p2, p3):
+    if p2[0] - p1[0] == 0:
+        if p3[1] - p1[1] == 0:
+            return True
+    elif p3[0] - p1[0] == 0:
+        if p2[1] - p1[1] == 0:
+            return True
+
+    return - (p3[0] - p1[0]) * (p2[1] - p1[1]) == (p3[1] - p1[1]) * (p2[0] - p1[0])
+
+
+for _ in range(N):
+    P = [(p1x, p1y), (p2x, p2y), (p3x, p3y), (p4x, p4y)] = \
+        map(int, input().split()), map(int, input().split()), map(int, input().split()), map(int, input().split())
+    if check90((p1x, p1y), (p2x, p2y), (p3x, p3y)):
+        (opox, opoy) = p4x, p4y
+        (remx, remy) = p3x, p3y
+    elif check90((p1x, p1y), (p2x, p2y), (p4x, p4y)):
+        (opox, opoy) = p3x, p3y
+        (remx, remy) = p2x, p2y
+    elif check90((p1x, p1y), (p3x, p3y), (p4x, p4y)):
+        (opox, opoy) = p2x, p2y
+        (remx, remy) = p4x, p4y
+    else:
+        print(0)
+        continue
+    if (opox - p1x) ** 2 + (opoy - p1y) ** 2 == 2 * (remx - p1x) ** 2 + 2 * (remy - p1y) ** 2:
+        print(1)
+    else:
+        print(0)
diff --git a/zeta_python/1918.py b/zeta_python/1918.py
deleted file mode 100644
index a702fe6..0000000
--- a/zeta_python/1918.py
+++ /dev/null
@@ -1,44 +0,0 @@
-import re
-OUT = []
-def turn_exp(start):
-    t = start
-    first = None
-    second = None
-    op = None
-    if tokens[t].isalpha():
-        first = tokens[t]
-        t += 1
-    elif tokens[t] == "(":
-        rr = turn_exp(t+1)
-        first = rr[1]
-        t = rr[0]
-        if tokens[t] == ")":
-            t += 1
-    if isinstance(first, str):
-        OUT.append(first)
-    if tokens[t] in "+-*/":
-        op = tokens[t]
-        t += 1
-
-    if tokens[t].isalpha():
-        second = tokens[t]
-        t += 1
-    elif tokens[t] == "(":
-        rr = turn_exp(t+1)
-        second = rr[1]
-        t = rr[0]
-        if tokens[t] == ")":
-            t += 1
-    if isinstance(second, str):
-        OUT.append(second)
-    OUT.append(op)
-    return t, [first, second, op]
-
-tokens = input()
-
-
-
-#_, parsed = turn_exp(0)
-#for o in OUT:
-    #print(o, end = '')
-# TODO: 중위 표기식의 연산순서 A+B+C 같은거
\ No newline at end of file
diff --git a/zeta_python/completed/1918.py b/zeta_python/completed/1918.py
new file mode 100644
index 0000000..83dadec
--- /dev/null
+++ b/zeta_python/completed/1918.py
@@ -0,0 +1,26 @@
+I = input()
+stack = []
+priority = {"*": 3, "/": 3, "+": 2, "-": 2, "(": 1}
+for i in I:
+    if i in "*/+-()":
+        if len(stack) == 0:
+            stack.append(i)
+            continue
+        if i == ")":
+            while stack[-1] != "(":
+                print(stack.pop(), end='')
+            stack.pop()
+        elif i == "(":
+            stack.append(i)
+        else:
+            while priority[stack[-1]] >= priority[i]:
+                print(stack.pop(), end='')
+                if len(stack) == 0:
+                    break
+            stack.append(i)
+
+    else:
+        print(i, end='')
+else:
+    for s in stack[::-1]:
+        print(s, end='')